I’ll share a real-world example I came across today.
Reading Hikaru no Go, I encountered a verb form (知らず) I didn’t recognize. Some googling led me to this explanation, which followed the standard pattern of giving separate rules for the two verb classes:
[quote]REGULAR VERB CONJUGATION FORMULA
A-form of the verb + ZU
IRU/ERU VERB CONJUGATION FORMULA
REPLACE the final RU with ZU[/quote]
But with our formulation, the rule is just: “Replace -ない with -ず.” I don’t need a separate rule because I already know the -ない form for all my verbs.
And this is quite common… almost all conjugations are simple derivations of either the -ない form or the -て form. Since both of these forms are common and you probably know them already anyway, why not use them?
…So today I gained a new grammar rule, so simple I’ll actually remember and use it! 