Discovered attacks
Are usually double attacks
Most typical - discovered check
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Q what if white's Queen was on d6; or e5 or even a3
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Bg1+ sets up a discovered attack - in this particular case black could not find
a place to put the bishop to attack
If the Queen were on a dark square such as e5 black would play
1Bg1+ 2 Kh2 (forced move) Bd4 - check with the Rook and the Queen has been won
note that this is not just a fork; but a double attack and discovered attack
the fork is not terribly dangerous without white's Rook on e1, since black could move
Queen to d6; d7 or e8 in that case
a better defence for black (though forced mate in 6) would have been
1.Kd1 Qxe2+, 18. Kc1 Qf1+, 19. Kc2Re2+, 20. Kb3 Qd1+ 21. Kc4 Re4+, 22.Kb5 Qa4 mate
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