1Major
3C 7-10 points, 4 card support
3D 10-12 points, 4 card support
3H /S3H after 1S
3S- over 11H OR 0-6 points, 4 card support
| An "ambiguous splinter" raise. An unbalanced, game-forcing raise promising 12+ points and 4-card trump support, with an undisclosed singleton or void |
Partner is expected to bid 3NT as an artificial relay, after which responder will show his singleton/void suit at the 4-level. A 4 C rebid by responder shows club shortness, 4 D shows diamond shortness, and 4H shows spade shortness.
2NT Jacoby
. With a balanced game-forcing raise, use the Jacoby 2NT convention instead.