過ぎたるは猶及ばざるがごとし

Calque of Literary Chinese 過猶不及 (guòyóubùjí). Analyzable as 過(す)ぎたる (sugitaru, perfective of 過(す)ぎる (sugiru, “too much”)) + 猶(なお)…ごとし (nao…gotoshi, “just like”) + 及(およ)ばざる (oyobazaru, adnominal negative of 及(およ)ぶ (oyobu), not enough)

過(す)ぎたるは猶(なお)及(およ)ばざるがごとし • (sugitaru wa nao oyobazaru ga gotoshi) ^{←すぎたるはなほおよばざるがごとし (sugitaru fa nafo oyobazaru ga gotosi)?}

1. doing too much is just as bad as not doing enough; too much of a good thing