Today’s winning 5-sec tactics

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ch-RUS Junior Girls Loo 2016.4.24 wfm Chernyak,Viktoria(2200)–wim Styazhkina,Anna (2300). Position before Black’s 31st move. A sharp game featuring opposite side castling. The White King is well defended. The problem, curiously, is that the same can not be said about the White Queen! (Hint!?)
BLACK TO PLAY AND CRUSH!
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ch-RUS Junior Girls Loo 2016.4.23 wim Styazhkina,Anna(2300)–wim Bivol,Alina (2368) Position after 24 moves. Another sharp game, Black having attacking chances down the h-file at the cost of a pawn. However, here White’s game is for preferance. Correct now would be 25.Qe2! with ideas such as Rh5 (trading a dangerous Rook) and/or Qe5 (gaining a dominant position over the Black Queen): for example, 25. Qe2! Rh4!? (25… Rh6 26. Qe5! Rh7 27. Re1 Rdh8 28. f4! and White is quite safe) 26. Qe5! with attack.
25.Rd1?

The idea is correct (trading a dangerous Rook before Black can double on the h-file) but the move falls victim to a stunning tactical refutation.
25…Qe4!!

This is the kind of shocker that gives one night mares! The Queen can not be taken because of mate on the backrank. Now if 26.Qc1 (the Rook must be defended also!)26. …Qh4! wins immediately: 27. Kf1 Rxd1 28. Qxd1 Qxg5 etc. That leaves only one other move…
26.Qb3!?

Now the rash 26…Qh4 would lose to 27.Qxb7+
26…a5!!

As simple as it is elegant! (Analysis shows that 26…Rd3 would also win) The threat is to chase the Queen away. Now 27.a4 solves nothing as 27…b5! leaves White with the same problem: 28.PxP a4! winning. And note that 28.c4 would be answered by 28…Pxc4!
27.Rf1!?

There is nothing better. The Black Queen can still not play 27…Qh4 because of 28.Qxb7+
27…Rh7!!

Planning to double and mate White along the h-file. There is now nothing to stop the Black attack…
28. Qb6!? Rdh8 29. f3
