It’s riskier to play the King’s Indian Defense than to play the King’s Gambit, said David Bronstein, who played both.

What he meant is that making positional concessions in order to obtain counterplay is more dangerous than sacrificing material.

When Black meets 1 d4 with 1 . . . Nf6, 2 . . . g6 and 3 . . . Bg7, his lack of space and mobility puts him in greater jeopardy than when White simply gambits a pawn with 1 e4 e5 2 f4.

But King’s Indian veterans also know that Black often has to give up material as well as space to obtain counterplay. That was the case in this week’s game when Jaan Ehlvest of the US played 18 . . . c4!.

The pawn cannot be held for long on c4, but Black was counting on compensating for its loss by using the c5 square and the a7-g1 diagonal. For example, 21 Bxc4 would allow a strong 21 . . . b5 22 axb6 Nxb6.

Later in the game, 23 gxf5 Nxc4 24 Bxc4 Qc5+ would win for Black.

After 23 . . . Qc5, White’s rook was pinned on d4 and the dark diagonal leading to his king was toxic, e.g. 24 Be3 Nxf3+ followed by 25 . . . Rxe3! and capturing on d4.