I Teach Kendo in Tokyo ITKIT

Tired of the rat race of the 21st century, Wang Jian transmigrates to 1980, hoping to start his life anew and seek his fortune.
Now living as Kiryuu Kazuma, he inherits a family dojo in Katsushika District, Tokyo. Blessed with a cute younger sister, a spacious house, and absolute freedom after both of Kazuma's parents died, everything seems to bode well for Kazuma's new life. Soon, however, all kinds of problems start to surface. Unable to recruit any students for the dojo, the Kiryuu siblings find it hard to make ends meet.
One day, they are horrified to find a dead rooster hanging outside their door. It is a death threat from a Yakuza syndicate, urging them to sell their dojo cheaply! What should Kazuma do? Please send help. It's urgent!
Never mind. Happiness is all that matters.
Now then, face the storm!
Kazuma with his newfound cheat is invincible!