Controlwood, conflicts with Splinter Bid. It is applied with support to major openning and slam points. Responder bids the suit which he needs control at the 4. level, if the opener do not have control, declares the game; but if he has the control then gives the number of Aces or keycards as in the Blackwood convention. In this sequence the openning suit will be skipped ofcourse. For instance, after 1 Heart openning 4 Diamond bid by the responder asks Diamond control and if the opener has Diamond control then the first step of the keycard answers will be 4 Spades. In this convention you can utilize DOPI and ROPI applications.