Coding the Russian alphabet for the purpose of mechanical translation

It is well known that there is in Russian a phonological opposition between palatalized and non-palatalized consonants (or, in the traditional terminology, between “soft” and “hard” consonants). This palatalization is marked in the Russian orthography by the use of one of the set of “soft” vowels or by the special “soft sign” according to whether the palatalized consonant is followed by a vowel or not. This immediately suggests the possibility of replacing the “soft” vowels by the “soft sign” + the corresponding “hard” vowels. Thus “Я” would be transformed into *ЬА, “Ю” into *ЬУ, etc. Furthermore, the “soft sign” and the letter Й are in complementary distribution, the “soft sign” being written after a consonant and Й being written after a vowel. They may therefore be regarded as “allographs” of the same “grapheme” and represented by the same symbol, Ь. The transformations suggested so far are listed here for convenience: