There aren't that many rules in chess. Movement rules for each type of piece then just a few
gameplay rules.
Yes, it's pretty easy to make a program really good at chess just by looking ahead a number of moves, because there is a fairly small set of moves possible at any given time.
You can also store tons of games between masters, and just look up what a master did in a given situation to win the game.
It's easy to just throw a ton of processor cycles or memory (or both) at the problem and solve it.
It's one of the reasons that Go is becoming popular in this country, there are way way more moves possible in a single turn in Go than in Chess, which makes it much harder to write a good computer program for, which is something that attracts players.