The Two Over One (2/1) Bidding System

Two Over One (2/1) Game Forcing is a natural, 5-card major bidding system. When the auction begins 1//, a simple 2-level response in a new suit is forcing to game. This page provides articles, convention writeups, and resources to help learn the system.

• What Is 2/1?
  A summary of 2/1, along with some benefits and drawbacks.
• When Is the 2/1 Game-Force "Off"?
  Exceptions to the "game-forcing" rule. This includes 2/1 responses in competition and other possible agreements per experts like Mike Lawrence and Max Hardy.

• Is It Necessary and/or Desirable to Make a 2/1 Response? by Bill Treble
  Things to consider choosing between a 2/1 response and other actions.

• The 1NT Forcing Convention
  An explanation of 1NT Forcing, a cornerstone of the 2/1 system. After partner opens 1/, a 1NT response shows 6-12 HCP and is a one-round force.

• The “Is It a Reverse?” Question by Bill Treble
  A discussion about the values promised by opener's reverses.
• Three-level Rebids in a New Suit by Bill Treble
  An explanation of jump and non-jump rebids by opener at the three-level.
• Raise or Bid Notrump with 3 of Partner’s Suit? by Bill Treble
  When to raise partner's suit or bid notrump when holding 3-card support.
• Jump Rebids in Notrump by Bill Treble
  After a 2/1 response, what does it mean if opener makes a 3NT jump rebid?

• Improving 2/1 Auctions: Part 1 by Fred Gitelman
  The way that most partnerships play 2/1 creates other problems that are not inherent to the system. The purpose of this article is to discuss some of these and to suggest some solutions.

• Improving 2/1 Auctions: Part 2 by Fred Gitelman
  A method for slam exploration at the 4-level after a partnership has already committed to a major-suit game.

• Improving 2/1 Auctions: Part 3 by Fred Gitelman
  An alternative approach to Jacoby 2NT, as well as improvements to the Forcing 1NT in the 2/1 bidding system.

• Serious 3NT by Marc Smith
  A way to discover extra values (or the lack of them) below game when playing the 2/1 bidding system.

• 2-Over-1 Partnership Checklist by Karen Walker (PDF).
  This a very thorough list of topics for partnership discussion. However, it does require familiarity with 2/1 and the implications of each treatment.

• 2/1 System Notes (383 pages, PDF) by Eric Kokish and Beverly Kraft
  A 2/1 game-forcing system by two longtime Canadian experts and teachacoers. Presented as a modified Kaplan-Sheinwold system, it features 5-card majors and frisky 11-14 1NT. A 2/1 response by an unpassed hand is always game-forcing.
• Pavlicek System by Richard Pavlicek
  An "almost-always" 2/1 game-forcing system with 5-card majors and a 15-17 1NT by American expert Richard Pavlicek. A 2/1 response is game-forcing unless responder rebids his suit. Also of interest is the wide-ranging 6-14 1NT forcing response to 1/.
• The Two-Over-One Game Force System (627 pages, PDF) by Neil H. Timm
  This 6th edition is a massive treatise on 2/1. It describes intrinsic 2/1 methods as well as optional gadgets. Neil also touches on topics like declarer play, defensive carding, and competitive bidding against Precision opponents.

• Bridge World Standard by The Bridge World
  A natural 2/1 system devised over the years by The Bridge World. It employs 5-card majors, 15-17 1NT, and a strong 2 opening. BWS is also the de facto system for The Bridge World's "Master Solver Club" bidding contests.