System on - 1NT/2NT

This is my latest blog entry in a series describing the basic Acol system that me and Anna play in Glasgow. Hope you're reading this Anna.

I've already mentioned that we can open a Weak 1NT with a good 5 card major, and only open 5422 if both doubletons are good.

Responses to 1NT opening

These apply equally for a 1NT opening and a 1NT overcall.

These are the continuations with Stayman. There's a subtle little twist here.

• Bidding 2♣ then correcting 2♦ to 2♥/2♠ shows a weak hand 5-4 in the Majors.
• Suppose you bid 2♣ and get a 2♥ reply. 2♠ is totally artificial and agrees Hearts as trumps. 3♣/3♦ show at least a 5 card minor and implies four Spades.
• The above also applies if partner replies 2♠; 3♥ sets Spades as trumps.
• After a positive reply to Stayman 4NT is quantitative, if you want to bid Blackwood you need to set trumps first by bidding the other Major.

For Transfers:

• Making a transfer then bidding the other Major shows a game forcing hand 5-4 in the Majors.
• Making a transfer then bidding 3♣/3♦ shows a game forcing hand with 5 in Major and at least 4 in minor, 5431 shape or better.
• Opener can jump accept with any 4 card support, he breaks the transfer with a good hand with 4 card support.
• After a transfer, 4NT is quantitative. If you want to bid Blackwood, then start with a 3 level response.

The other possible responses to 1NT:

• 3 of any suit is a slam try in that suit, showing a good six card suit. If the bid is 3♣/3♦ opener bids 3M if they have a 5 card major. Otherwise, opener bids 3NT with a weak doubleton in responders suit, and cuebids with anything else.
• 4♣ is natural (not Gerber). We never bid this though.

Checkback Stayman

We rebid 1NT with 15-17, and 2NT with 18-19.

• If you've got the right strength then prioritise rebidding NT over showing a 4 card Major.
• If you have 18-19 then the usual rebid is 2NT; 3NT is only used if you are very flat (4-3-3-3).

Responder can show a 5-5 hand with a jump after a 1NT rebid, or a weak six carder by rebidding his suit.

2NT responses

2NT opening shows 20-22. Opening 2♣ then rebidding 2NT shows 23-24. As far as possible, the responses are the same as over 1NT. One difference though

• If you bid Stayman and then correct 3♦ to 3♠, as before this shows 5 Spades and 4 Hearts. But it's no longer a weak hand, just giving a choice of games.

The reason for doing that is to stop you going beyond 3NT.

They interfere with our 1NT

After a double we play Helvic. After any artificial interference (e.g. 2♣ showing Majors) our double shows that suit (e.g. Clubs). Over a natural interference, such as 2♥ showing Hearts and a minor, we play naturally:

• Double is penalties.
• 2♠ (any bid at the 2 level) is weak and natural.
• 2NT is natural.
• 3 level bids are strong and forcing, e.g. 3♣ or 3♠.
• A cuebid is Stayman, such as 3♥ here, which asks partner if they have Four Spades.

Our defence to their 1NT

We play competitive doubles, see here. A double of a 1NT opening shows 14+ and balanced. These other bids are about 9-13:

• 2♣ - 54 or better in Majors (depends on vulnerability). Partner bids 2♦ to ask for the better Major, or if he has a strong hand and will invite game next time.
• 2♦ - six card Major.
• 2♥/2♠ - 5 of the Major and at least a 4 card minor. Partner bids 2NT to ask for the minor.
• 2NT - minors

3 level overcalls don't happen much but would be some sort of very shapely hand.

To finish, a jumping horse.