This convention uses the bid of a Minor suit overcall after a strong 1 No Trump opening or a weak 1 No Trump opening to show a particular distributional holding and can be employed either in the immediate seat or in the balancing seat. The terminology comes from the names of the bridge players, who devised the convention: Mr. Paul Allinger – Mr. Roger STern – Mr. Larry ROssler. The schematic for the entire original convention is shown below.
- 2 Clubs: Shows a 5-card Heart suit and an unspecifed 4-card Minor suit.
- 2 Diamonds: Shows a 5-card Spade suit and an unspecified 4-card second suit, called the Anchor Suit.
The Astro bidder (Intervenor) promises nine cards in two suits. The high card points should be mainly in the two suits and should be stronger if vulnerable. The high card points are a matter of partnership agreement, although it is imperative that the held values be mainly in the two suits indicated. The recommended values lies within the range of a minimum of 9 and a maximum of 14 points. The general guideline is that the Astro bidder hold at least two of the top five honors.
The Astro bid can be made as a direct overcall or in the pass out seat.
Advancer and Responses
The partner, (the advancer), of the Astro Bidder has several options, which are explained below.
1. The partner can bid two of the specified Major, showing at least three card support and no game ambition.
2. The partner can bid three of the specified Major, which becomes an invitation.
3. The partner can bid four of the specified Major, which is a natural bid.
4. The partner can pass indicating a weak hand and a long suit in the Minor suit bid. This can be done with a 5-card suit if that is the partnership understanding, but a 6-card suit is preferred.
5. The partner can bid two of a neutral suit, specifically the next higher ranking suit above the Astro bid, which is a negative action, denying the ability to make any other response. The partner shows less than three card support in the specified Major and no length in any Minor suit.
6. The partner can bid 2 No Trump, which is artificial and forcing, and which shows some support for the specified Major, suggesting game prospects but does not guarantee a further bid.
7. The partner can bid a new suit as a takeout or jump. The jump can also include the neutral suit. Both cases show a six card or longer suit.
After a neutral bid, the Astro bidder has several options.
1. He could pass with five cards in the neutral suit. Remember, the Astro bidder shows nine cards when he bids 2 Clubs in Hearts and an unspecified Minor, which could be the neutral suit.
2. He could show five cards in the specified Major by bidding it.
3. He could bid his second suit, the unspecified Minor, at the level of three, strongly suggesting a six-card suit and more strength in high card points and distribution.
Pass: Promises a weak holding, a minimum of a 5-card support in the suit of the overcall.
- 2 Diamonds / 2 Hearts: An artificial first response; a Relay asking the Intervenor to bid/name second suit and denies sufficient support for the anchor suit. If the anchor suit is Hearts, then the relay is 2 Diamonds. If the anchor suit is Spades, then the relay is 2 Hearts.
- 2 Hearts / 2 Spades: Accepting the anchor suit, but showing weak values and at least a 3-card suit. The intervenor may pass.
- 2 Spades: After 2 Clubs Hearts is the anchor suit and a new suit promises at least a 6-card suit in Spades and denies support in Hearts.
- 2NT: This first response is forcing and game-invitational with a maximum of 11 points with values in all suits. Shows a doubleton in the anchor suit and requests intervenor to name second suit, which the advancer may pass.
- 3Clubs: After a 2 Diamonds by intervenor showing Spades as the anchor suit, this first response shows a 6-card suit in Clubs and denies support in the anchor suit.
- 3Clubs / 3 Diamonds: This is a raise of the artificial overcall of the intervenor and promises at least a 6-card suit and is considered game-invitational.
- 3 Hearts / 3 Spades: Promises at least a 4-card support for the anchor suit, and values based on points and distribution. Invitational in nature, which intervenor may pass with minimum or bid game with maximum.
- 4 Hearts / 4 Spades: Promises at least a 4-card support for the anchor suit and game values based on points and distribution. Generally considered to be a sign-off against an opening by the opponent of a strong No Trump.
Note: Variations of the Astro convention are somewhat dependent on the bidding system employed and can be altered or varied to meet the requirements of the particular bidding system.
Note: Some partnerships have agreed that the distribution of the holding, when overcalling could / may be reduced to 4-4 in both Major suits regardless of the state of vulnerability, otherwise the distribution is generally 5-4, 4-5, or 5-5 depending on the state of vulnerability. This is entirely a partnership agreement in all employed variations of the concept.
There have been several variations to the Astro convention, and you can click on the following links to discover these modifications.
- Modified Astro – A variation of the Astro convention.
- Pinpoint Astro – A variation of the Astro convention.
- Astro Cuebid – An invention to indicate a two-suited holding after an opponent opens the auction on the one level with a suit bid.
Note: Another modification, origin unknown and with no official designation, has been employed by bridge partnerships using the Roth-Stone bidding system and these players have adapted the original concept to meet the requirements of this particular bidding system. The overcalls are outlined below in the schematic.
The student of this concept will note that the Major suit overcalls are one level higher. This may be indicating either a preemptive strike against the No Trump bidder or actual values held plus working values held in the indicated suits. The student will also note that the lack of the 2 No Trump and both Major suit overcalls on the two level are not employed and have become idle bids.
Note: Another variation, origin unknown and with no official designation, employs all the otherwise idle bids to more accurately designate the suit or suits and employs also the double as penalty. The origin of this variation is unknown.
The employment of the 2 No Trump bid to show both Minor suits distinguishes this variation from the other variations.