A method of defending against 1 no trump openings based on ASTRO.
The term astronat is used to designate the overcaller, and the term relay to describe the responses in the neutral suit. Astro is varied in three respects:
- Major two-suiters are bid differently. The two Club overcall is often used with a major two-suiter. With five spades and four or five hearts, the astronaut bids two clubs and follows with two spades over the relay. With four spades and five hearts, the treatment varies with the strength of the overcaller's hand. Normally, he bids two clubs followed by two hearts, giving responder the opportunity to show spades. With a stronger hand he bids two diamonds followed by two no trump.
- Pronounced two suiters (6-5 or 6-6 distribution) Specific bids are laid down for each two-suiter hand:
Two no trump black suits
Three clubs minor suits
Three diamonds red suits
Three hearts major suits
With the odd two-suiters, (Spades - Diamonds or Hearts - Clubs), bid two of the minor suit and follow with a jump in a six card suit.
3) A redouble by the astronaut or the responder is an S.O.S.
