The black queen is attacked by the rook on e1. What should black play?
Black can ignore the attack on his queen because white has a back rank problem, therefore:
27. … Txb3! 28. axb3 Rd1 This is now possible because the bishop is eliminated!
29. Te4 Df1+ 30. Rxf1 Rxf1#
Source: 1001 Chess Exercises for Club Players door Frank Erwich (New In Chess) (New In Chess).