This is simply a set of ideas on how to run a campaign based on East Asian concepts, primarily Japanese.
Classes
Fighter - this can be used for samurai (for higher status characters) or bushi or ashigaru for lower status characters.
Mage - the best match is an onmyouji, which in folklore would summon and control spirits
Cleric/Paladin - the sohei (warrior monk) would be a fair match for either class; the historical sohei was somewhat similar to a European Crusading order
Thief - the yakuza would be the best fit here, with involvement in stolen goods (tekiya) and gambling (bakuto)
Assassin - ninja
Witch - kitsune-tsukai, a person who had the services of a fox spirit as a trickster and illusionist
Weapons are fairly straightforward name changes:
Ono - a battle axe or great axe
Kama - a sickle (treat as hand axe)
Kanabo/Tetsubo - a two-handed, studded war club (treat as morning star)
Tanbo - a short staff, the length from wrist to elbow (treat as club)
Bo - a long staff (treat as staff)
Chigiriki - an iron staff connected to a chain and weight (treat as flail)
Bisento/Naginata - pole arm
Wakizashi - short sword
Katana - sword
Nagamaki - two-handed sword
Yari - spear
Tanto - dagger
Yumi - longbow (uses Ya arrows)
Armor
O-yoroi - heavy lamellar armor (AC 6)
Tanko - banded plate (AC 5)
Karuta - chain and plate armor (AC 4)
Gyorin Kozane - "fish scale" armor (AC 3)