Understanding grammar in 五省

Question

There is a set of daily reflections said to be used in Japan's Navy, one being:

至誠{しせい}に悖{もと}る勿{な}かりしか
translated as "Hast thou not gone against sincerity"
(source https://en.wikipedia.org/wiki/Gosei_(meditation))

• 至誠に悖る as in roughly "to oppose to sincerity" seems understandable
• 勿かり closest word in Jisho seems to be 勿れ, marked as particle, I couldn't find what exactly 勿かり is or how it was formed
• しか 's か should be the "question mark" か, as for し it may perhaps be a stem of する? I don't recall seeing 「しか」before though

Is there some archaism or neologism involved?
The only guess is that 勿かり is a stem of a newly? formed verb formed from 勿れ, used as in {Vstem}する. That would be a verb formed from "must not" (maybe could be reworded to "avoid doing"?), modified by 至誠に悖る, finally as in "did you do the avoiding of 'opposing to sincerity'?" - is this correct?
If so - I have read おstemする expresses humility, お is missing here, but is this the nuance used here?
Thank you!

Answer 1

「至誠{しせい}に悖{もと}る勿{な}かりしか」

I suggest that you pretend to be seeing the kana「な」 where it gives you the kanji 「勿」 for quick comprehension purposes.

「至誠」 = "sincerity"

「悖る」 = "to be out of line with"

So, 「至誠に悖る」, while "looking" difficult, should look modern as far as grammar. 「noun + に + verb」. Pretty normal stuff, yes? Look up 至誠 and 悖る and you're good to go.

The rest of the saying, however, is in Classical Japanese.

「なかり」 is the 連用形{れんようけい} ("continuative form") of the classical adjective 「なし」, which means 「ない」.

「し」 is the 連体形{れんたいけい} ("attributive form") of the past-tense subsidiary verb 「き」.　The modern version would be the famous 「た」.

So, 「なかりし」, in Modern Japanese would be 「なかった」. Things are now starting to make sense, don't they?

「か」 is a sentence-ending particle for calling someone's attention or reminding a person of something. It is the same in Modern Japanese.

" I have read おstemする expresses humility, お is missing here, but is this the nuance used here?"

Where is "here"? Are you saying we should say 「お至誠」? If so, no, that sounds way too funny. Nothing is missing from this saying, I assure you. Unnecessary honorifics do more harm than good.

Hope this does not cheapen my own answer, but a modern Japanese TL of the saying would be something like:

「まごごろに反する（こと/もの）はなかったか。」