The Kaigaku RPG is a retroclone that blends simple OSR rules (by way of the Black Hack) and inspiration from famous samurai-themed games. You can use this book to play intense duels between bushi, wars of words among courtiers, ninja missions and more.
This book is the free, no-art, no-frills version. It has everything you need to play. We'll be kickstarting the game soon to purchase art and other services to create the best possible product. The expanded version is going to have many more schools for you characters to attend, a detailed bestiary, lots of cultural notes, pre-made adventure/hooks, a mass battle system, a new class (the Artisan) and a more in-depth look at the setting.