う and る verbs
Differentiation between u-verbs and ru-verbs is simple.
All verbs that end in u except verbs that end with ru are u-verbs.
There are u-verbs that end in ru however. The way to tell ru-verbs and u-verbs that end in ru apart is to look at the vowel sound preceding the ending ru. If there is an i or e before the ru it is a ru-verb. If the ru is proceeded by any other vowel, the verb is an u verb.
Here are some examples of う verbs:
よむ- To read
かく- To write
のる- To ride
Here are some examles of る verbs:
たべる- To eat
みる- To look or to see
ねる- To sleep
かえる- To return(u-verb)