Chess is 1,500 years old. It started in India and spread everywhere. There are six kinds of pieces, and each one moves differently — that's the whole game.
The knight is the only piece that jumps over others — it always moves in an L (two squares one way, one square sideways).
The queen is the most powerful piece — she moves like a rook + a bishop combined, in any straight line.
The king can only move one square at a time, but if you trap him you win the game. That's "checkmate".