CardShark BidBase
Splinter Bid

3=Weak, 4=Strong

1-3 is a "Random Splinter" (a singleton or void in an unspecified suit) with 10-12 HCPs. Opener can sign off at 4 with no interest in slam, or may bid 3N to ask responder to bid the suit with the singleton/void.

1-4/4/3N shows a singleton/void in Clubs, Diamonds, or Spades, respectively, with 13-15 HCPs.