Chess develops logical thinking, ability to think in the abstract and mental independence.
The chequered board was introduced from about the eleventh century. Before that, all the squares on a chessboard looked exactly the same ...
This wonderful video (2.2mn) comes from our Brazilian member Charles Moura Netto, based in Santa Maria de Jetiba.
We are sure your kids will love this, but if they are going to try it for themselves, make sure they notate their games - it will be excellent practice for them (no more reading the letters and numbers from the edges of the board!).
Charles has set up a discussion group at www.linkedin.com which may develop into a very useful forum.