This convention defense method was devised by Mr. Robert Mosher of San Francisco, California, United States, and also bears his name. This defense method is employed after an opponent has opened the auction with No Trump. Whether or not the concept can / should be employed only in the immediate seat or also as a balancing action is dependent on the partnership agreement. All competitive overcalls are natural.

Contribution by Mr. Robert Mosher

Mr. Robert Mosher played very often with Mr. Jeff Rubens and Mr. Roger Stern during the 1950s and 1960s and scored better with this natural defense method than with other, more complicated defense methods. Many thanks to Mr. Robert Mosher for his additional explanations.

Note: The Official Encyclopedia of Bridge refers to this defense method as whimsical, mainly owing to its non-complexity, but it is generally the bridge community, which more or less decides the most preferable and descriptive adjective.

Note: Mr. Robert Mosher was also kind enough to contribute the following email message, which is quoted unchanged. We also thank Mr. Robert Mosher for taking the opportunity to email us with this information and contributing this information for the benefit of bridge players and the bridge community. We are indebted to Mr. Robert Mosher.

Dear bridgeguys.com,

I got a kick out of your site, especially when I found my innovative convention from my duplicate days in the late 50's & early 60's in your glossary. I refer, of course, to Mosher over No Trump, which was really not intended comically.

In those days my most frequent partner was Jeff Rubens (yes, the current editor of The Bridge World) and our group of friends / partners / opponents included Roger Stern, one of the inventors of Astro. I believed then, and still do, that the natural defense (i.e., Mosher) works better than artifical vs. a 1NT opening and refused to play Astro, so my system got a name. By the way, it consistently produced better results than Astro, at least when in my skilled hands, and if you don't believe me, ask Jeff!

Best of luck with your site and trump breaks.

Robert Mosher - Email dated: April 21, 2002

Principles of the Concept

The idea behind the concept is to keep the overcalls as simple as possible, and bids which did not require long memorization. The following outlines the meanings of these overcalls.

Double:	Any double is for penalty. Partner must pass.
2 :	Promises a long, generally a 6-card plus Club suit.
2 :	Promises a long, generally a 6-card plus Diamond suit.
2 :	Promises a long, generally a 6-card plus Heart suit.
2 :	Promises a long, generally a 6-card plus Spade suit.

If you wish to include this feature, or any other feature, of the game of bridge in your partnership agreement, then please make certain that the concept is understood by both partners. Be aware whether or not the feature is alertable or not and whether an announcement should or must be made. Check with the governing body and/or the bridge district and/or the bridge unit prior to the game to establish the guidelines applied. Please include the particular feature on your convention card in order that your opponents are also aware of this feature during the bidding process, since this information must be made known to them according to the Laws of Duplicate Contract Bridge. We do not always include the procedure regarding Alerts and/or Announcements, since these regulations are changed and revised during time by the governing body. It is our intention only to present the information as concisely and as accurately as possible.