Mate in 2

We have an unusual setup: the white queen on e5 is pinned, and funnily, its pinner—the bishop on f6—is itself pinned by the rook on h6.

1.Qc3! sets the solution in motion, simultaneously clearing the fifth rank for the g5 rook while maintaining control over c7. With this, Black is now confronted with the threat of 2.Rb5#. They have five ways to defend against it, but each defence carries a secondary flaw, enabling White to deliver mate in a different way.

1…Re5 shuts off the fifth rank, preventing Rb5, but ends up unpinning the queen. Hence, White delivers 2.Qc6#. By the same logic, 1…Ne5 also prevents Rb5 but succumbs to 2.Qc5#.

1…Be8 guards the b5 square, but it also unguards a8, allowing 2.Nxa8#.

1…Rxc7 removes the guard of the b5 square—hence, thwarting mate with Rb5—but now, the c7 square is blocked. Thus, White has 2.Qb2#. Alas! There’s no Bxb2, as the hapless bishop is pinned! Analogously, 1…Nxc7 runs into 2.Qd4# (self-block+pin-mate).

In the last two variations, the Q delivers mate while being itself pinned by the f6 bishop. A move by a pinned piece is known as a Pelle move in chess problem terminology. 2.Qb2 and 2.Qd4 are fine examples of the same that also come with checkmate.