Slavic nouns ending in -ьjь and their relation to *i-declension

The article analyses Slavic nouns ending in -ьjь, which were earlier thought to be connected with the *o-type declension. The author demonstrates a correlation between some of such nouns and the *i-type, and presents and proves a hypothesis that in a number of cases the element -ьj- serves as a means of transition from the *i-type to the *-jo-type.