難かがたかん

がたかん · gatakan

suffix 連体形

難か is the form before a noun of 難し — difficult, hard.

Classical Japanese — you’ll mostly meet it in older texts and set phrases

How it’s built

難し難か

Form before a noun (連体形). In modern Japanese it looks like the plain form; it sits right before a noun: 食べる人 (a person who eats).

This spelling is the version with ん (sound change before で/だ): 読ん → 読んで.

難し is a classical japanese conjugation, so it follows that pattern.