Japanese verb groups are very simple to understand, but I have found various people confused about them.
Calling them “u-verbs” and “ru-verbs” certainly doesn’t help! It’s one of the sillier things the textbooks have come up with. All verbs end in the u-sound but only a small number actually end in う. And more る (ru)-ending godan (so-called u-verbs) than there are る (ru)-ending ichidan (so called ru-verbs)!
Go-dan figure! So let’s take a simple, rational look at Japanese verb groups. You’ll be using them a lot, so it’s a good idea to get them right from the start.
And it’s not nearly as hard as the textbooks make it!