After learning iaijutsu and other techniques to combat firearms, Mitsurugi sought a sword appropriate for a new style of fighting. He finally
settled on Shishi-Oh. An incredibly well-balanced Japanese sword, it is
Mitsurugi's preferred weapon.
During the intense training that he followed after his defeat in front of his lord, Mitsurugi became dissatisfied with his old katana Korefuji and replaced it with Shishi-Oh, a katana with a wider blade. With this blade Mitsurugi perfected many new sword fighting moves to defeat the rifle.
It is revealed that during the 17 year gap between Soulcalibur IV and Soulcalibur V, Mitsurugi lost Shishi-Oh to a female swordsman. She managed to shatter the katana, but Mitsurugi, seizing upon a chance, punched her in the stomach and took victory.
In Soulcalibur, Shishi-Oh was wielded by Arthur as well. This is because Arthur replaces Mitsurugi in countries that discouraged samurai imagery and references. When Arthur entered Soulcalibur III he wielded Gassan, one of Mitsurugi's optional weapons in Soulcalibur II.
In Soulcalibur V, Shishi-Oh is Mitsurugi's legendary weapon and is unlocked upon reaching Level 41.
Shishi-Oh (1P) in Soulcalibur II
Shishi-Oh (2P) in Soulcalibur II
Mitsurugi wielding the Shishi-Oh in Soulcalibur
Player 2 Mitsurugi wielding the Shishi-Oh (2P) in Soulcalibur
Mitsurugi, wielding the Shishi-Oh in Soulcalibur II
Player 2 Mitsurugi, wielding the Shishi-Oh (2P) in Soulcalibur II
Mitsurugi, in his bonus costume, wielding the Shishi-Oh in Soulcalibur II
Mitsurugi wielding the Shishi-Oh in Soulcalibur III
Player 2 Mitsurugi wielding the Shishi-Oh (2P) in Soulcalibur III
Mitsurugi with the Shishi-Oh sheathed in Soulcalibur IV
Player 2 Mitsurugi with the Shishi-Oh (2P) sheathed in Soulcalibur IV
Mitsurugi wielding the Shishi-Oh in Soulcalibur VI