conquering the academy with just a sashimi knife

"If I slash, it will be cut." I, who was once called the best swordsman in the nation, have ended up in a mobile game I've only spent money on a few times. And I’ve even received the blessing of the 'Sword God'! But… the only weapon I can use is a sashimi knife? Just one minute a day. I become a Sword Saint with a sashimi knife.