QGD: THE TWO QUEENS TRAP
Mayet-Harrwitz, Berlin 1848
Chess Board
6.KtxP?? . . KtxKt!
White's error: he thinks Black dare not reply 6..KtxKt.
Chess Board
7.BxQ . . B-Kt5 ch
White seizes Black's Q but Black checks White's K.
Chess Board
8.Q-Q2 fcd . . BxQ ch
White is forced to sacrifice his Q.
Chess Board
9.KxB . . KxB
And Black should eventually win, having taken a piece (Kt for P).
6.Kt-B3 would be a better move for White, when 7.KtxP could then be a threat to Black. Example ends: Undo or Jump or Clear