A tachi forged by Gojou Kuninaga. He had gone through several owners (one of them being Oda Nobunaga, so he is often depicted in fanworks alongside other swords owned by him), and was stolen from his owners twice; once from the grave of Sadayasu of the Adachi clan, and also from a shrine by Koudeki of the Honami Clan. He is currently part of the Imperial Collection alongside Ichigo Hitofuri, Uguisumaru and Hirano Toushirou.
Because of how he tended to be stolen from his resting place, and because of his long life in general, Tsurumaru has a love of surprises and likes to sneak up on people to surprise them. This has naturally earned him a reputation of being a troll in fanworks who plays pranks on the other characters for his own amusement.
His name is written with the kanji for "crane", and he often references how he resembles one due to his white clothing. Ironically, despite cranes representing longevity and good fortune in Japanese culture, most of his masters did not live long.
