じゃなかったです is split into じゃ and なかったです about ichiran HOT 4 CLOSED

The last updated just shows when the page was generated so it's pretty useless on dynamic pages, but I left it in to detect problems with caching.

I don't think this particular construction is common at all, or grammatically correct. じゃなかった is already formal-negative-past form of a verb. です is superfluous because we're already formal by using じゃない. Moreover it confuses the segmenter because なかったです is a valid formal-negative-past conjugation of ない. And じゃ is a contraction of では so this split might actually make more sense in terms of being grammatical.

from ichiran.

Apologies if I'm wrong here (you'd definitely know more about this than I'd do) but I'm getting conflicting information. In the construction of a polite, negative, past tense of an adjective/noun it's listed in here as (as well as Genki) as being じゃなかったです. It also explicitly lists じゃないかった as being the plain form.

Also, in the conjugation of the copula, this website shows じゃなかったです as being the polite negative past tense form. I haven't being able to find any information about じゃなかった being the formal form of a verb (?). I've seen that です is excluded when the adjective is used to modify a noun.

from ichiran.

No, you're right, I actually have です implemented as a suffix specifically for cases like this (negative plain form + です instead of the usual -ません), however in case of じゃなかったです it gets blocked by an existing low-scoring word.

from ichiran.

Fixed in 41342e0

from ichiran.