Regular verb classes

Contrary to the typical way these classes I presented, I opt for treating only nidan and yodan as "regular" verb classes, with the reasoning being these are the only classes which don't have only a small fixed number of verbs belonging to it. Additionally, the irregular verb classes can almost always be traced down as a variant/hybrid of the regular classes

Yodan (~75% of verbs)

form suffix example
root - yom
mizen -a yom-a
ren'you -i yom-i
shuushi -u yom-u
rentai -u yom-u
izen -e yom-e
meirei -e yom-e

Shimo-nidan (~20% of verbs)

form suffix example
root - hajim
mizen -e hajim-e
ren'you -e hajim-e
shuushi -u hajim-u
rentai -uru hajim-uru
izen -ure hajim-ure
meirei -eyo hajim-eyo

Kami-nidan (~5% of verbs)

form suffix example
root - ot
mizen -i ot-i
ren'you -i ot-i
shuushi -u ot-u
rentai -uru ot-uru
izen -ure ot-ure
meirei -iyo ot-iyo

Irregular verb classes

Ichidan

The ichidan class is closed, as the vast majority of modern ichidan verbs actually come from nidan.

form suffix example
root - mi
mizen mi
ren'you mi
shuushi -ru miru
rentai -ru miru
izen -re mire
meirei -yo miyo

Ichidan is considered a variant of nidan