In Cyrillic uncial style (as in Greek), for the two letters Н and И (shapes N and H), the vertical columns are drawn wide and the line between is thin.

In the Cyrillic letter Н with the Greek shape N, the descending diagonal "\" will progressively become shorter: See for example: One of the explanations may be the management of the virtual line horizontally dividing the letters as А,Б,В,Є,Ж,З,Н,К,Х,Ч,Э,Ю.

From the 15th century, the poluustav [ru] (en in Russian) a semi-uncial style developed, and is notably still used today by the Church Slavonic publishing.

In 1517, a work of simplification and "romanization" of the Cyrillic alphabet by the first Belarusian printer François Skorina (Prague and Vilnius editions) will give a writing of capitals close to modern.

Then the official Civil Script made it mandatory to use the H-shape for the letter Н (in use at that time, see Karion Istomin's alphabet book from 1694) at the detriment of the original N-shape.

No specific explanation is available for this choice and if there was a problem with readability, it could have been decided to return to the original shape as in the Greek or Latin alphabet.

We can only note that the Church prefers to continue using the old shape, thus refusing to reverse two ghlyphs in the Cyrillic alphabet created specifically to translate the Bible, and thus avoiding repeating the instability of this H-shape (cf.