Assertion: combination | /r/HasProperty | sound
Facets:
Source sentences:
text: A combination must be sound.
text: and without the adversary having any effective defence if the combination is sound – a certain advantage such as the gain of material (a pawn, the exchange, a piece), a mating attack, improvement of the position, and finally (in the case of starting from an inferior position) a draw by stalemate, perpetual check, or reduction of force below mating strength.