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Baki Wiki
Jack Hanma
Jack profile
Kanji Name ジャック 範馬
Kana Name ジャック・ハンマー
First Appearance
Anime Start!
Manga The Festival Has Begun!!
Origin Canada
Age 21
Hair Color Blond
Height Debut: 193 cm (6'4")

Later: 243 cm (8'0")
Later: 275 cm (9'0")

Weight Debut: 116 kg (255 lbs)
Later: 211 kg (465 lbs)Later: 255 kg (525 lbs)
Fighting Style Pit Fighting & Goudou & wrestle
Original Dub Kouichi Sakaguchi (2001)
Kenta Miyake (2018)
English Dub Christopher Swindle (2018)
Relations Diane Neil (Mother)
Yuujirou Hanma (Father)
Baki Hanma (Half-Brother)
Unnamed Grandmother
Yuuichirou Hanma (Grandfather)
I never once planned to live a long life! I've long been ready to exchange the strongest body ever for death.

– Jack to Dr. John.

Jack Hanma (ジャック 範馬, Jakku Hanma) is a fictional character from the Baki the Grappler series. He's a pitfighter from Canada and the son of Yuujirou Hanma and Diane Neil, a Canadian United Nations operative who Yuujirou met during the Vietnam War. Like his brother, Baki Hanma, he has since childhood wished to surpass his father in strength and martial ability. In the English dub of the second anime series, his name has been changed to Jack Xamma because of dub issues (pronounced "Zah-mah").

His ringname is Jack Hammer (ジャック・ハンマー, Jakku Hanmā). In the fifth manga series, he is also known as the "Biting Cyborg" (噛みつき サイボーグ, Kamitsuki Saibōgu).


Jack's driving force is wanting to defeat his father, Yuujirou Hanma, to avenge his mother who was raped by him. After taking super steroids that made himself beyond unstable, Jack turned into a monster without balance who only cares about becoming stronger to take revenge.

Jack is an incredibly determined and stubborn person; he just doesn't know when to quit. His overtraining would be suicidal, if not for a mad scientist's steroid cocktails being part of his regimen. He's had his skeleton surgically restructured multiple times to get bigger. Even having half his face bitten off by Pickle and waking up in the hospital twice, the second time from a severe coma, he still gets up and goes right back to it. Also, it can be said that he is sometimes too confident in his strength. He trains too much for his body to handle, forcing him to resort to steroids and other medical methods in order to keep his strength growing steadily. He is too obsessed with beating Yuujirou and avenging his mother, to the point where he is blinded by that dream. He doesn't know many techniques and often fights head-on. Jack doesn't care if he has to sacrifice his own life to achieve his goal, saying that he's always been prepared to die if he gets a body strong enough to defeat his father.

He refuses to hold back against his opponents; and, speaking of behavior, he prefers to act like a wild animal rather than a true fighter, as especially shown how he bites his opponents during their fights, making him even more animalistic. Jack can indeed seem very frightening to his enemies: for example, he startled Pickle after Jack lost to him, because there is nothing in the wild that prepared the caveman to the sight of a prey seemingly coming back from the dead for a rematch. He almost out-savaged Pickle during their fight and the caveman came to see him as a wasp, the only creature he fears.

He sees his brother, Baki Hanma, as a rival, but also likes and cares for him deep in his heart as they have the same goal in surpassing Yuujirou. Following his defeat at the hands of Baki, he became more humble and amicable towards his half-brother. He learned to calm down and grow friendlier towards others. He also has perfect table manners and sometimes feeds the koi with little old man Tokugawa. Jack also seems to have some feelings for his younger brother's girlfriend, Kozue. When he first meet her in the Maximum Tournament, he flirted with her, although he might have only done this to provoke his brother.

Jack's intelligence is relatively average. Although he has shown himself to be a bit of a combat genius from time to time (as he was able to counter Shibukawa's Aiki). This is likely due to his lineage as a Hanma and the son of Yuujirou.

After being defeated by Izou Motobe, Jack reforms himself and understands he will never be as strong as he wanted, focusing only in brute force. He understood that he needs to learn more fighting. Therefore, he created an original fighting style "Goudou", which consists in using his signature move: biting. Jack now looks more mature, calmed and composed. Tokugawa pointed out that Jack has learned from his defeats and has changed for the better.


Screenshot 2021-01-09 at 1.39

Jack Hanma in the manga.

Jack trained so hard that he completely destroyed his body. He took an experimental drug known as the x4 to strengthen his body, regardless of a scientist warning it might kill him, he underwent extreme pain from the drug surviving due only to his Hanma blood line, the drug caused his muscles to become extremely large and strong. Unfortunately, excessive use of drugs eventually managed to destroy his body again, drastically reducing his life expectancy in the process. But later, Jack managed to repair his body and he became even stronger. In the second series of the manga, he underwent surgery to make him taller and stronger. Kureha Shinogi carried out the operation, and thanks to that fact the desired effect was achieved. Kanji Igari stated that Jack is even bigger than Mount Toba.

His physical features include blue eyes, a piercing gaze and short blonde hair and rather large eyebrows. He's often wearing a blue t-shirt, long jeans or shorts. In the third season of the anime, Jack's eyes are brown. It can be said he looks very much like Yujiro in terms of his facial appearance and his physique looks to be similar to his grandfather Yuuichirou. The only thing he has from his mother is her hair color. Similar to Baki, he has scars all over his body as a result of overtraining.

Jack is an extremely tall and muscular man. His initial height was 6'4" (193 cm), which changed to about 200 cm after the Maximum Tournament thanks to Shinogi Kureha's limb-lengthening surgery, and finally to 8'0" (243 cm) after Jack's fight with Pickle, which was once again achieved by the limb-lengthening surgery. After Izou Motobe had shattered all of his teeth, Jack now possesses titanium dentures.



Diane Neil, Jack's mother, was a secret agent whose job was to get rid of Yuujirou Hanma during the battlefield. When the Ogre discovered that Diane was trying to outsmart him, he decided to take revenge on her and raped Diane. That's how Jack was born. Yuujirou, unlike with Baki’s mother, did not kill her and Jack’s mom decided to keep the kid. Unlike his half-brother Baki Hanma, he has since childhood wished to surpass his father Yuujirou Hanma in strength and martial ability to get revenge rather than earning his love and respect (later, Baki also wanted to get revenge, of course).

Jack before drugs

Jack's former look.

His obsession to defeat his hated father led to extreme over-training at various fighting gyms which led to the deterioration of the muscles in his body. He wasn't much more than skin and bones because his body had been damaged by overwork. For example, Jack would punch sandbags for over 12 hours without eating, resting, or even using the restroom and would lift weights until his body refused to do anymore. He claimed he will never be able to defeat his father with normal training. After his encounter with the Yuujirou-inspired scientist named Dr. John who witnessed Yuujirou killing a polar bear, the scientist promised him great results if he tries using a special drug which he called X-4. He received from him a concentrated formula of steroids to match his over-training and gained immense power in the process, though in the process Jack had become addicted to the drugs and began overdosing leaving him even more mentally unstable. At first, the doctor was happy with Jack's results, but at one point he tells the Canadian that he's really starting to overdo completely, although the doctor finally agreed to give Jack as much drugs as he wanted. Like Yuujirou, he became powerful enough to kill a polar bear with his bare hands, but with his unstable mindset he was more brutal and made it's death agonizing.

Baki the Grappler[]

Maximum Tournament Saga[]

Jack appears in the Maximum Tournament in the Underground Arena, but introduces himself as "Jack Hammer", in order to not reveal his true identity to everyone. Before his first match begins, Jack meets Kozue Matsumoto in the hallway of the Underground Arena. He starts talking to her like he's trying to flirt. Suddenly, angry Baki appears and shows a very militant attitude towards Jack. The Canadian fighter just turns around and tells Baki he wants to see him in the finals.

Jack vs silva

Jack fighting Sergio Silva.

Jack's first opponent is Sergio Silva, the Brazilian grappler. The fight is quite short and very one-sided. At the beginning of the fight, Sergio catches Jack with some grappling hold, but he is completely defenseless against the destructive power of the Canadian, who easily comes out of the hold using just pure physical force. Silva doesn't have the slightest chance against Jack, who eventually sends him into the air with an uppercut and wins the match. After the fight, Yuujirou Hanma enters the arena to talk to Jack. Yuujirou sees that Jack's using drugs to strengthen his body. After a while, he gets excited and tries to start a duel with him, but then Baki enters the arena, kicking Jack in the face. Baki screams that Jack has no right to fight the Ogre and he is the only one who will defeat him. Jack tells him that Baki's not the only one who has the right to do so, but it is unknown what he really want to say by it. Annoyed Yuujirou knocks Baki out so he won't disturb them, and after a while Jack whispers something in Yuujirou ear that makes him very happy. The Ogre smiles and announces that Jack has a great right to fight him. The Canadian competitor leaves the arena with a cold and calm expression.

Jack vs kengo

Jack biting Misaki Kengo.

Before starting another fight in the tournament, Jack meets Alexander Gallen in the locker-room and tells him that he is interested in a fight with him. A tense and conflicting relationship begins to form between the two competitors. In the second round, Jack's opponent is Kengo Misaki, the Japanese master of Shorinji Kempo. Misaki tries his Shorinji Kempo techniques, but nothing works. Something strange happens during Misaki's rush, because his hand is flooded with blood. For unknown reasons, it turns out there is a wound on it. At some point in the battle Misaki knocks Jack to the ground and starts bombarding him with kicks from above. However, this time a wound on the foot of the Japanese appears unexpectedly. During their fight, Jack uses his teeth to bite Misaki's body. He tears his hand and leg apart with his teeth, doing it in such a discreet and instant way that nobody notices that he used his own teeth. Mitsunari Tokugawa even interrupts the fight to see if Jack is using some kind of weapon. When it turns out that Jack doesn't have any items with him, the fight continues. The Japanese is trying to use another Shorinji Kempo techniques, but this time the Canadian fighter stops hiding the using of his teeth and bites into Misaki's hand in front of everyone, then knocks him out with a brutal punch.

After the match, Jack meets Alexander Gallan again, but this time in the hallway. Gallen accuses him of being disgusting in his fighting style that is not graceful at all. Jack explains to him that he sees the fighting in a slightly different way. At the end of the conversation, Gallen just adds that he can't wait to fight Jack and goes away slowly.

Jack vs gallen

Jack punching Gallen.

In the third round of the tournament, the dispute between Jack and Gallen is finally resolved, because Gallen is the next opponent of Jack. At the beginning of the match, Gallen dominates and hits Jack with his fists, performs suplex on him and then manages to perform his powerful technique called Gallen Special. At some point, however, Jack decides to start some counterattack and eventually almost bites off two of Gallan's fingers. The Russian is furious that Jack has disfigured the body representing Gallen's homeland and rushes at the opponent, but then Jack attacks with a powerful uppercut and then starts bombarding him with the violent blows. The Russian wrestler takes a lot of damage, but in an act of desperation, he still tries to perform a suplex. However, the Canadian neutralizes his technique and throws him into the arena fence. Gallen clearly begins to lose the fight, which Jack ends with a powerful nukite aimed at the ribs and a brutal punch to the heart. Gallen spits out a lot of blood that makes Jack's face dirty, and then the Canadian is declared a winner.

Jack vs shibukawa

Jack vs Shibukawa.

In the semi-finals, Jack faces Gouki Shibukawa, the old jujutsu master. Before the match begins, Jack makes a show of strength in the arena. He pulls out a big coconut and starts tearing it apart with his own teeth. Shibukawa takes a sip of water just before the start of the battle, and after a while shoots a water from his mouth towards Jack. The shot hits a vital point called the "tear cable". It's a trick that makes Jack feel like he's drowning in water for a while. Shibukawa goes on the offensive and throws him very hard on the ground and then jumps on him with a kick while Jack is lying on the arena's floor. Shibukawa thinks it's the end of the fight and wants to leave the ring, but Jack suddenly bites his ankle. The Canadian attacks Shibukawa in various ways and starts to dominate, and the old jujutsu master defends himself using his special weapon called Aiki. Jack repeatedly tries his brutal attacks on the old master, but each time it ends with his fall to the ground. Soon, however, Jack finds a way to deal with this technique. He decides to approach the old man very slowly, so that he wouldn't be able to give back the impact power and knock him over again. In this way he bites his hand and then attacks Shibukawa with a few brutal blows. At the end of the fight, Shibukawa tries to use some technique with the last remaining force against the opponent, but when he clutches his hands on the Canadian, this time it is Jack who uses Aiki and throws the old man to the ground, finishing with a kick from above. Shibukawa lies semi-conscious on the ground, and Jack is declared the winner and leaves the arena.

When the match ends, Jack is stopped in the hallway by Shinogi Kureha, who advises him to not take part in the final fight because of too much drugs that Jack's body has taken. Kureha says the Canadian fighter's body will be completely destroyed in the next fight. Jack laughs at him and ignores his warnings. Desperate Kureha tries to use force against Jack to stop him, but it turns out to be completely ineffective. The Canadian tells him he's stronger even when the drugs doesn't work anymore. For a while, they're arm wrestles with each other and Jack wins easily with one hand. When the Canadian fighter leaves, Kureha still screams that Jack is about to die, but any attempt to convince him is futile.

Jack vs baki

Deformed Jack kicking Baki.

The final fight is coming up, and Jack's gonna face Baki. Before entering the ring, Jack meets Yuujirou in the hallway. They talk for a while and Jack tells him that he's going to beat him next. A Canadian fighter enters the arena in a coat with the "Jack Hanma" inscription, thus revealing his real name to everyone for the first time. The brothers shake hands before the fight, smile at each other and promise to do their best. From the beginning, their fight is very fierce and both combatants performs their best techniques. At some point, Jack bites through Baki's brachial artery, but he quickly bandages his wound to lengthen his time before he bleeds out. Eventually, Jack's body starts to deform due to too much drugs he took, and he starts screaming and vomiting painfully in the arena, but does not intend to stop fighting. The "mutated" Jack beats his brother with a lot of blows, but Baki keeps fighting and eventually decides to use the Front Neck-Lock. Jack gives his best to withstand his brother's grappling technique, but eventually loses consciousness. After the match, Jack helps tired Baki raise the winner's belt. When Jack leaves the ring, he meets his father Yuujirou again in the arena's corridor and after telling that he's finally ready to fight him, Jack attacks Yuujirou. Unfortunately for him, Yuujirou counterattacks, biting him very brutally and then knocking out his son in the blink of an eye. Jack Hanma falls to the ground and Yuujirou gets mad at him for losing twice in one day.


Most Evil Death Row Convicts Saga[]

After the Maximum Tournament, Jack has Kureha Shinogi perform surgery to lengthen his bones where multiple of his bones were broken and he had his limbs lengthened in 8 places. Jack is then first seen by Kaiou Retsu in a restaurant where Jack orders an entire roasted pig for himself and eats it in 10 seconds, even though Retsu is at first unaware that it's Jack and judges his height, saying it could be more than 210 cm. Jack then stands up and walks up to Retsu and says that he just remembered who Retsu was and that he saw him in the underground arena and at the Maximum Tournament. This shocks Retsu and makes him realise that it's Jack. He afterwards wonders on how Jack managed to gain 20cm (Jack was 6'4 the last time they met, meaning that Jack is 6'11 at this point in the series). Jack silently walks away with Retsu looking at him, still wondering on how Jack grew so much in less than a year.

Jack and kureha e e

Jack with Shinogi Kureha.

After this, Jack goes on to another restaurant with Kureha Shinogi, where Jack orders a T-Steak and ends up eating the bones like biscuits, leaving the waiters surprised and wondering if he's a professional wrestler. Meanwhile, Kureha compliments Jack's growth rate, calling it a miracle, and explains the limb-lengthening surgery Jack underwent in 8 places after the Maximum Tournament. It turns out that after the tournament they established a much more friendly relationship than at their previous meeting. After he finishes, Jack says that he doesn't care about brotherhood, but he can be the one who gets revenge for Kureha Shinogi. This is probably a reference to the loss Kureha suffered from Jack's half-brother Baki Hanma in the Underground Arena. However, it can be also a reference to the fact that Hector Doyle almost killed Kureha's brother Koushou Shinogi.

Later, Jack is seen confronting Sikorsky, the Russian serial killer and one of the five death row convicts. He tells Sikorsky that he is simply an enemy to him and asks where should they fight, mentioning that the police in Tokyo can be annoying. They decide to fight in an empty public bathroom. Jack strikes first with a punch which Sikorsky barely avoids. Sikorsky then grabs onto an emergency fire extinguisher on the ceiling with his thumb and index finger and kicks Jack in the face. Jack shakes off the attack and compliments Sikorsky's finger strength, before questioning for how long he can hold on like that. He charges at Sikorsky again and grabs his leg, making Sikorsky repeatedly kick Jack in the face with the other in order to release himself, but Jack punches Sikorsky so hard that Sikorsky breaks the emergency fire extinguisher and flies of to the end of the bathroom and throws up. After this, Jack and Sikorsky go to a phone booth where an unsuspecting civilian Shou is making a call. Sikorsky enters first and Jack second. After a short fight, Jack knocks out Sikorsky and orders for the phone booth to be transported into the coliseum via a truck. It turns out that Jack was helped by Kanji Igari, who wanted to take revenge on Sikorsky for insulting and beating him up.

Jack vs sikorsky e e

Jack fighting Sikorsky.

After this, Jack enters the arena while the truck releases Sikorsky and Mitsunari Tokugawa explains the situation to him. Sikorsky then starts yelling loudly before taking off his shirt and screaming: "давай!", which in this context means "bring it on!" in Russian. Sikorsky strikes first and Jack tanks his strikes, only to lift Sikorsky up after Sikorsky tries to push Jack into the wall. Jack throws him into a wall on the opposite side and then rushes to him and kicks him so hard that Sikorsky flies into the audience. Sikorsky then decides to take an old man's staff, as well as a nail from a wall broken by his body while he was being tossed by Jack, and use them as weapons. Jack notices this and lets Sikorsky use the staff as a spear. Sikorsky tries to stab Jack, only for the spear to stop without piercing even his abs. Jack says that unless it's an actual spear it won't pierce his abs. Sikorsky then throws the wrinkled nail in Jack's face, but Jack catches it with his teeth and proceeds to chew it. After a short while he spits the nail out, showing that he almost made it into a gum thanks to his incredibly strong teeth. Seeing this, Sikorsky thinks to himself that Jack isn't human while Jack says that it's time for a switch and that Sikorsky will get a opponent worthy of him. At this point Gaia starts walking into the arena while Jack starts leaving. They meet half-way and Jack gives Gaia a high-five before exiting the arena.

Godlike Clash of the Kids Saga[]

He is challenged by Mohammad Alai Jr, in preparation for fighting Baki. After going to an abandonned lot, he brutalizes Jr, to the point he can no longer stand up.

Hanma Baki[]

Pickle Wars Saga[]

Jack is one of the Underground Arena fighters who have infiltrated the US Army base in Japan to meet the prehistoric caveman Pickle in person. After knowing that Pickle is sleeping inside a tree trunk, Jack kicked the tree to wake Pickle up. In response, Pickle peed onto the bulletproof glass and almost onto Jack.

Some time after the Pickle's gruesome fight against Katsumi Orochi at the Tokyo Dome has concluded. Jack unceremoniously barged into the Underground Arena to meet Pickle in person. Before the fight, Jack has taken hundreds of drugs and substance in preparation for his fight, after which he leaves a trail of discarded empty bottles and packages along the way. Pickle is excited to see someone with an equal height to him and started the fight immediately. After a brief exchange of blows, Jack challenged Pickle to a biting contest to see who has the strongest teeth. Both giants then charged at each other and started trying to bite each other's lips off. Pickle ended up winning as he lifts Jack's huge body using only his mouth, and then threw him away at such a great speed that he rips Jack's lower facial skin off of his face. Enraged, Jack launched barrages of punches at Pickle, but only managed to excite the caveman enough to use his Leaning Forward Stance. Pickle then charged at Jack at full speed, but the fighter managed to parry the blow, sending Pickle flying into the spectator's area. Jack then grabs Pickle and threw him back into the ring and bite the caveman's left ear off. After became aware that he has lost a body part, Pickle became furious and started bouncing off the fence, dodging all of Jack's attacks. Pickle then proceed to brutally beats Jack down, breaking his jaws and almost all of his teeth, and knocked him out. As Pickle is about to devour Jack, Pickle suddenly saw an image of a giant wasp - the only animal that he feared - above Jack, and then retreated back to his corner. This is because Pickle believed that Jack was dead, but he still sense the danger coming from him. This ended up to be true, as when Mitsunari approached Jack's unconscious body, he was almost struck by Jack's middle fingers that moved on its own. Had Pickle chose to finish Jack off, Jack's fingers would be able to pierce Pickle's skull and kill him.

Despite his injuries, Jack escaped from the hospital and returned to the Underground Arena for a rematch. Pickle initially ran away from Jack and went to the outside of the Tokyo Dome, as he believed that Jack has somehow managed to come back from his "death" a few days prior. Pickle then confronts Jack, as he wanted to defend his pride as a fighter, and quickly defeats Jack for a second time. He then hanged Jack's unconscious body by his feet on top of a skyscraper so that he could "eat" him later. After Jack was rescued and returned to the hospital, he immediately attempted to return to the arena for a third round, but is stopped by his half brother Baki, who warned that if he wanted to do it again, he would be eaten by Pickle for real. This caused Jack to cried out in despair, accepting defeat.

Strongest Father and Child Quarrel Saga[]

Jack is briefly seen watching the live broadcast of the father and son fight between Yuujirou and Baki. Sitting among a pile of drugs and substances. He is then breaking down in tears, and lament how his father has never give him a chance to have an all-out bout like baki.


He declares his intent to fight Musashi Miyamoto but Tokugawa has him fight Motobe first. Motobe ties him up and removes all his teeth.

Baki Dou[]

After Izou Motobe shattered all his teeth, he had them replaced with titanium dentures. He tells Tokugawa that he plans to create a martial art based solely around biting. After Nomi no Sukune the 2nd pushes his face, Jack eats his pinkie. They decide to have a formal arena match later. During the fight, he strategically bites off parts of Nomi's shoulder and heel as the latter attempts to attack him. After a tough and bloody battle, Nomi finally succeeds and suplexes Jack on his face; however, he soon collapses due to blood loss and Jack is declared the winner, finally breaking his losing streak.


Being one of the offsprings of Yuujirou Hanma, Jack is among one of the strongest fighter in the Baki series. His strength is shown many times in the story: he killed a polar bear with his bare fists in the same way his father did, he defeating the convict Sikorsky with a punch so strong that he lifted the telephone box they were in, and later withstood Sikorsky's knuckle slash in the Underground Arena. He could take many blows from Mohammad Alai Jr and defeat him, cutting Jr's tongue by punching him hard in the face. He also managed to punch Pickle over hundred meters away despite the strength difference and making him run away in fear by causing him to view him as the only creature that scares him, a wasp.

Even before he made use of drugs, young Jack has exhibited an inhumanly strong body resilience. When Jack was a child, he is capable of lifting his own body using only his thumbs for several hours, despite having his blood pouring out of his eyes and nose due to staying in an upside down position for a very long time. Even after young Jack collapsing due to exhaustion, he would wake up to repeat the training again. In his teenage years, Jack trained so hard that his body shrank into skeletal frame due to these brutal training burned away all of his muscle gain. But despite this, he is still being able to forcibly put himself through brutal training, despite his condition would be considered fatal for a normal human otherwise.

Jack is notable for his extremely high pain tolerance. His body is strong enough to surpass the adverse effect of drugs, even though he used more than thousand times of the "lethal overdose" limit for a normal human. He is able to endure the immense pain from several limb extending surgeries that even Yuujirou admit that he wouldn't be able to went through it. Due to his super steroids, Jack had a tendency to fight like a rabid animal (prior to his invention of "Goudou") and has severe determination to finish fights through to the end which proves this even further. His great determination and ferocity in battle allow Jack to continue fighting even suffering serious injuries, such as when he broke his right arm and vomited over 20% of his bodily fluids in the fight against Baki, when he had half if his facial skin ripped off by Pickle, as well as when he got his foot pierced by Motobe's blade and later lost all of his organic teeth during the same fight.

One of his main techniques is biting, and his biting force is equal that to a crocodile which is hard enough to easily crush wood with his teeth. He claims that his teeth can tear a coconut. Jack could eat a whole roasted pig in 10 seconds and could chew on the bones of a T-bone steak like it was a biscuit, thanks to the amazing power of his teeth. His bite is strong enough to damage Izou Motobe when he wears chain mail made of Aramid fibres, which is made for planes and tires, although he did lose all of his teeth in the process. After creating the "Goudou" and received titanium teeth implants, Jack perfected the strength of his bite, being able to sustain his huge body on a tree just by biting a towel that was tied to it. He was also able to lift huge weights for a long time with just the strength of his jaw.

Despite using brute force to fight, Jack is a very tactical fighter, and is smart enough to counter and outmaneuver his opponents. For example, he made Chiharu Shiba pass out with a special type of a hold where Jack presses two fingers on the gang leader's vital points that are located in the throat (Baki defeated Gaia with a similar way; except that Baki did it with two hands, while Jack only used one hand) and also when he found the weakness of Aiki after being thrown many times and used a similar move to defeat Gouki Shibukawa. During his fight with Pickle, Jack tried to strike his middle fingers into Pickle's ears, piercing his brain. He used this as a last-ditch attack, because he was about to be knocked out and used his fighting spirit to activate this technique. This move may have possibly killed Pickle, if the massive caveman hadn't managed to sense Jack's upcoming attack.

Ever since his loss against Motobe's ancient kenjutsu, Jack has made major improvements to the power of his masseter; strengthening his bites. Since biting is Jack's signature technique, it has become his martial pursuit and have devoted himself to it. Traveling around the world, Jack has finally completed his technique in Taiwan and mastered his skill. He calls it "Goudou", the way of biting. He also had a full set of artificial titanium teeth surgically implanted in his mouth since he lost all of his original teeth during his fight with Motobe. From the results of his "Goudou", Jack is capable of forming a 500 yen coin in a triangle-like shape by using his artificial teeth. His sight has improved to the point that he is able to see countless of major and minor blood vessels, similar to x-ray vision. Jack himself have stated that his "Goudou" allows him to sees all animals and all humans as nothing more than dense clumps of vital points. With "Goudou", Jack can bite and tear off opponents' critical blood vessels in moments before they know it, often causing them to pass out due to severe blood loss.

With his biting technique, Jack can also counterattack any strike aimed at his face with a quick and hard bite; he managed to rip off the little finger of Nomi no Sukune the 2nd when he hit him in the face and tear his heel when the sumo wrestler kicked him in the jaw causing him to lose a lot of blood from his injuries. After a tough fight, Jack managed to defeat Sukune, who has a grip strength superior to even Yuujirou, and was recognized as one of the strongest characters in the series, with no particularly huge injuries.


  • Bite – Jack's signature move; used against Kengo Misaki for the first time.
  • Chop-Blow – used against Alexander Gallen.
  • Suplex – used once against Alexander Gallen.
  • Nukite – used against Alexander Gallen.
  • Feint – used once against Gouki Shibukawa.
  • Fastest Dash – used against Gouki Shibukawa.
  • Aiki – used once against Gouki Shibukawa.
  • Lion Dance – used against Baki Hanma.
  • Stomp – used once against Mohammad Alai Jr.
  • Axe Kick – used once against Izou Motobe.
  • Rear Naked Choke – used against Noro, Tokugawa's Tibetan mastiff.
  • Tackle – used against Nomi no Sukune the 2nd.
  • Jab – used against Nomi no Sukune the 2nd.



  • He is based on the legendary British professional wrestler Dynamite Kid.
  • During his fight with Sukune the narrator nicknamed him "Jack the Ripper" for the way he was shredding Sukune's flesh with his bite, tearing off parts of it similar to the real-life serial killer who shredded his victims to pieces.
  • Within the wider story Jack serves as a dark parallel to Baki, showing what would have happened had Baki abandoned his more traditional training methods and instead abused steroids, surgery, and other artificial means of increasing his strength.
  • Jack is implied to be significantly weaker because all of his attempted shortcuts, while his ability to remain competitive is suggested to be because of his Hanma lineage.