One of the most popular and efficient modern slam conventions is Roman Keycard Blackwood (RKB). But it does suffer from two serious drawbacks:
- Kantar's technically strong full version is immensely complicated, requiring serious memory work and a fair bit of partnership discussion about sequences leading up to it.
- It can get you too high: in the majors, having decided to ask and getting the wrong answer, you are committed to playing at the five level. It's worse in the minors, where often you cannot afford to ask for fear of missing five of the minor.
The Chilli implementation of RKB is simple and coherent, well integrated with the rest of Chilli and covers more than 90% of the useful technology in RKB. Exchanges usually take place in the game zone, allowing you to stop in game when missing two keycards. In that respect, it resembles Kantar's Kickback RKB, but it can be rolled out more routinely.
The middle game zone side-suit is RKB, showing values for at least six. Responses are:
| +1 | nought or three keycards |
| +2 | one or four keycards |
| +3 | two or five but no trump queen |
| +4 | two or five and the trump queen |