Is kōkutsu dachi driving you around the lean? Or should that be the bend?

Have you ever wondered why in both kōkutsu (後屈, こうくつ, ko-u-ku-tsu) dachi (立ち, だち, da-chi) and zenkutsu (前屈, ぜんくつ, ze-n-ku-tsu) dachi, which you may often be told are back leaning stance and forward leaning stance respectively, that you shouldn't lean at all and your body should be upright?

The reason for this is that kutsu (屈, くつ, ku-tsu) doesn't mean lean but actually means bend. The dictionary definition of kōkutsu is retroflexion or back bend and of zenkutsu is anteflexion or foward bend. In the context of a karate stance however the back (後) and front (前) part would refer to the knee that is bent. So we have back knee bent stance and front knee bent stance. No leaning involved at all.

The kanji that is read as kō in kōkutsu is the same kanji that is read as ushi(ro) in ushiro geri (後ろ蹴り, うしろげり, u-shi-ro-ge-ri), back kick, and the kanji that is read as zen in zenkutsu is the same kanji that is read as mae in mae geri (前蹴り, まえげり, ma-e-ge-ri), front kick. So the kanji have the same meaning in each case but are read (pronounced) differently.