Russian short adjective: слабее

Chess writers have a pet grammatical tic, at least in English and Russian: they put comparative adjectives at the front of a sentence, as in "Better is 10. Bxf6" or "Worse is 15…Rb8". I suppose this frames the content of the sentence and ensures that its point doesn't get lost among the moves.

I tripped over one of these in Romanovsky's "Romanticism in the Art of Chess"¹ - my incorrect English translation is on the right:

Слабее is a short-form comparative adjective derived from слабый, weak.

Anna Semeonoff summarizes this well in "A New Russian Grammar", 4ed rev., 1944:

§ 180. There are three degrees of comparison in Russian: positive, comparative and superlative, e.g., нобый (new), новее or более новый (newer), новейший or самый новый (newest).

§ 181. The comparative degree is formed from the positive by changing the ending -ый or -ой into -ее (or ей). This form can be used only predicatively (i.e. like the abbreviated form of adjectives), and is therefore not declined, e.g.

Этот дом красивее.
This house is prettier.

§ 182. When the object of comparison is mentioned, the comparative is followed either by the genitive, e.g.

Он умнее брата.
He is cleverer than his brother.

or by чем (than) with the nominative, e.g.

Наш дом красивее, чем ваш.
Our house is prettier than yours.

Слабее Х

’Weaker is X’, or ’X is weaker’

Слабее, чем Х

’[Something is] weaker than X’

So the passage from Romanovsky should be translated thusly: