The Chilli neutral bidding space logically arranges itself into three layers, and both partners bid their suits upwards through these layers always making the lowest bid possible.
| first layer | 1 , 1 , 1NT, 2 and 2 |
| second layer | 2, 2, 2NT, 3 and 3 |
| third layer | 3, 3, 3NT, 4 and 4 |
A suit bid in the first layer shows at least four cards and denies the ability to make a cheaper bid. So if you have at least four hearts, you will bid 1 first, regardless of how many cards you have in the other three suits. With no heart suit, but with at least four spades, you will bid 1 first, regardless of how many in each minor suit. With no major, a club suit is bid before diamonds.
Both partners continue to show their suits in ascending order through the second layer, where a suit bid normally shows at least five cards and again denies the ability to make a cheaper bid.
In the third layer, a suit bid sets that suit, and the auction continues as a fit auction. Setting the suit unilaterally in this way should ideally show a good six-card suit, but occasionally you may be forced to do so on a poor six-card suit, and partner should be alert to that possibility if the bidding goes high.
| Hand A | Hand B | Hand C | Hand D |
|---|---|---|---|
| AQ84 | AQ84 | AQ842 | AQ842 |
| K8732 | K873 | K873 | K8732 |
| K92 | K92 | K92 | K9 |
| 2 | 32 | 2 | 2 |
On all these hands, open or overcall 1, and respond 1 to 1 or 1. What if partner then responds with 2 or 2 ? On hands A and B the spade suit is dead, so rebid 2 with hand A and 2NT with hand B. With hand C, rebid 2 to show four hearts and five spades. And with hand D, rebid 2 to show the five hearts – as we shall see later, if there is a five-three spade fit, it will still be found.
| West | North | East | South | ||
|---|---|---|---|---|---|
| AQ876 | 1 | pass | 1 | pass | 54 |
| 3 | 1 | pass | 2 | pass | K10864 |
| AK76 | 2 | pass | 2 | pass | Q5 |
| A75 | 2 | pass | 2NT | pass | K1053 |
| 3NT | pass | pass | pass |
instead of 2. Similarly, reverse West's spades and diamonds, and he would rebid 3 instead of 2. 2NT was forcing as East's hand was unlimited.| West | North | East | South | ||
|---|---|---|---|---|---|
| KJ109743 | 1 | pass | |||
| 5 | 1 | pass | 2 | pass | |
| A9 | 2 | pass | 2NT | pass | |
| 1082 | ? |
, setting spades without limiting. A small point: if partner has shown no length in a suit that you set (as here), you should assume that he holds a singleton for slam bidding purposes.