Tatsuuma Ushiyama (牛山 辰馬, Ushiyama Tatsuuma), also known as Ushiyama the Undefeated (不敗の牛山, Fuhai no Ushiyama), is one of the Abashiri Convicts and a crucial member of Hijikata's Group. He is a master judoka and one of the strongest and most dangerous fighter in Hokkaido.
Ushiyama is a large hulking Japanese man of very muscular build. He has short spiky dark hair, dark deep set eyes, defined cheekbones, and a prominent brow ridge. He sports a thick chevron mustache. His ears are of peculiar "cauliflower" shape, and on his forehead there's a big square bump that is part of his skull . His muscular torso and back have the typical Abashiri Convict tattoo.
Ushiyama usually wears a black three piece suit with a white shirt, a black tie, a black vest, and black dress shoes.
Ushiyama is an ambitious and hedonistic man. He enjoys good fights with worthy opponents and having sex with women he considers attractive. He is usually pragmatic and serious and has an air of danger about him. He threads with prudence, regularly offering reasonable advice to Hijikata. He can be sarcastic and sometimes cracks dry jokes.
Ushiyama has an unquenchable sexual desire. Unless he regularly sleeps with a woman, Ushiyama becomes violent and, as Hijikata jokes, can even come at men. He is very direct with his sexual advances. However, Ushiyama considers himself a gentleman and claims to have respect for the prostitutes he sleeps with, calling them Kannon bodhisattva.
As a judoka, Ushiyama relishes fights and challenges. When he met Sugimoto, he was impressed favorably by his strength and befriended him. Ushiyama is confident in his fighting prowess to the point he will challenge a (although weakened) bear in combat.
- Expert Judoka: In order to increase the power of his sweeps, Ushiyama practices kicking a 60kg bag of rice every day. In fact, his sweeps are good enough that most opponents often find themselves flipped head over heels before they even register what's going on.
- Great Physical Strength: Ushiyama possesses a level of might which few can match, being able to easily lift and throw a full-grown adult across a room and through ceilings. In fact, he was able to easily block an attack from a Kodiak Bear before tossing it around. His charge are equal to that of Hijikata's kick that was capable to kill a full grown horse
- Great Physical Toughness: Beside his near superhuman strength, Ushiyama is more then capable of coming out unscathed from almost any kind of damage, with his skull in particular being so incredibly thick that not even a slash from Hijikata's katana could pierce it.
- Ushiyama likes peaches and beer and has no dislikes.
- He was modeled after Tatsukuma Ushijima, a Japanese judoka and former All-Japan judo champion. His nickname was "The Demon Ushijima".
- Ushiyama is taller than Ariko and Tanigaki, making him the tallest character in the series.
- According to Golden Kamuy anime character reference sheet, Ushiyama's height is 188 cm (6'2). 
- Ushiyama is heavier than Tanigaki and Sofia, making him the heaviest character in the series.
- In 2018 Golden Kamuy All-Stars popularity poll, Ushiyama ranked 17th, gaining 2,406 votes. 
- In the VIZ Media English translation and fan-translations, Ushiyama's name is translated as Tatsuma instead of Tatsuuma.
|Main Group||Anji Toni • Kantarou Okuyama • Kirawus • Rikimatsu Ariko • Shinpachi Nagakura • Tatsuma Ushiyama • Toshiyuki Kadokura • Toshizou Hijikata|
|Former Members||Hyakunosuke Ogata • Kamezou • Kano Ienaga|
|Associates||Kenzou Tamoto • Kiroranke • Takuboku Ishikawa • Yoshitake Shiraishi|
|Main Group||Asirpa • Saichi Sugimoto • Yoshitake Shiraishi|
|Former Members||Cikapasi • Fusatarou Oosawa • Genjirou Tanigaki • Inkarmat • Kiroranke • Retar • Ryu • Vasily|
|Associates||Hajime Tsukishima • Hyakunosuke Ogata • Otonoshin Koito • Tatsuma Ushiyama|