My opponent was a weak player, so he didn't see it coming. But I was pleased with the tactic nonetheless :) Try it out for yourself!

I think you are lucky your opponent was so weak. The 1. Ka1 and and 3. bxc3 are the worst moves imaginable. Puzzles usually contains 'forced moves' played by your opponent, which are basically the only moves the opponent can move which does not result in a serious disadvantage for the moving player.