The above position is from a tricky puzzle i saw online- it may seem simple but is very difficult as I couldnt work out why it works White to move. the answer is 1 Rc8+ Rxc8 2 Qa7+ Kxa7(or 2...Kc7 3 bxc8+ Kxc8 4 Qxe7) 3 bxc8=N+(ie underpromotion wins) 3...Kb7 4 Nxe7 and a piece up is an easy win there.  Its from an actual game by the 2nd World Champion Emanuel Lasker against an annominous player.