Developed by J.G.Ripstra. Applied to show three suited hands over 1 NT opennings, but the majors should be at least 4-4 distribution. 2 Clubs overcall shows the other three suits, 2 Diamonds again shows the other three suits. 2 NT overcall shows 5-5 distribution.
2nd Opponent choose one of the three suits if the overcall is 2 Clubs or 2 Diamonds. But if the overcall is 2 NT, he can not know the long suits and he declares his longer suit according to the original version of the convention. It may cause problem and the opponents may have to play at the 4th level. In order not to encounter such a problem 2 NT overcall should be used to show 5-5 major distribution.