It's a gameless Saturday night here in Busan, so I created this little graphic to show the class relationships in Chanbara.
The points of the triangle have classes with only one special ability type: Samurai - Combat Maneuvers; Ninja - Tricks; Yamabushi - Spells. Call these the base classes, if you will.
The secondary human classes have primarily the same special abilities as their group's base class, but also some of the special abilities of the group along the lines of the outer triangle.
So, for example, Gorotsuki are in the Shinobi group but along the line with Maho-tsukai, so they have mostly Tricks but some Spells. Onmyoji are in the Maho-tsukai group but along the same line, so they have mostly Spells but some Tricks. The three Yokai classes have an even split of the two ability types that flank their boxes. So Kitsune have an even split of Tricks and Spells.
If you were to write it out in linear form for each side of the triangle, it would look something like this:
Ninja - all Tricks
Gorotsuki - 2/3 Tricks, 1/3 Spells
Kitsune - 1/2 Tricks, 1/2 Spells
Onmyoji - 1/3 Tricks, 2/3 Spells
Yamabushi all Spells
Repeat for the Samurai to Ninja line, and Samurai to Yamabushi line.