If the RKB bid is not available – because partner raised directly to game or they interfered in the game zone – the cheapest side-suit is RKB. There are no equivalents to the values for five and one and none bids, and all other side-suit bids are EKB.
As we have seen earlier, in a fit auction 4NT is always natural and never RKB.
| West | North | East | South | ||
|---|---|---|---|---|---|
1 | 2 | ||||
| 2NT | 4 | pass | pass | ||
4 |
, the normal RKB bid, is unavailable, so 4, the cheapest side-suit bid, RKB.| West | North | East | South | ||
|---|---|---|---|---|---|
 KQ5 | 1 | pass | 3 | pass | AJ73 |
| A983 | 4 | pass | 4 | pass | KQ642 |
| K4 | 5 | pass | 6 | pass | A87 |
| 9875 | pass | 6 |
is a splinter, agreeing hearts and showing values for at least the three level. Opposite such a favourable splinter, minimum flat opener is now every bit worth game. Responder checks that West has at least one keycard with 4 RKB and then bids a typical low point slam with a good fit.