Mohan

Several of my partners (including Ed Davis) prefer John Mohan's defense against weak notrumps. We define "strong" to be "any 1NT opening that includes 16 HCP, but in addition 13-15 HCP played in conjunction with a big club system." All weaker than that are "weak."

The basic idea is to use transfers in order to give the overcaller a chance to bid twice with very good hands. Initial actions are:

Dbl  Good 14+, usually balanced
2C:  Both majors
2D:  Transfer to hearts
2H:  Transfer to spades
2S:  Spades and a minor
2NT  Hearts and a minor
3C:  Natural
3D:  Natural
3H:  Natural, preemptive
3S:  Natural, preemptive

Note that initial actions are sound overcalls. Most overcalls are something that resembles a decent opening bid with some playing strength. This means that we might get shut out with 13 vs. 13, but since it is quite possible that we have a game, we can't afford to bid light and get doubled at the 3-level after a game try.

Advancer's Actions

After an initial double, some play system on, some play natural. In either case, I suggest making a 2C: response to the double be a scramble, not showing much of anything, just usually fear. It might be a reasonable shapely hand that doesn't want to play 1NT doubled and doesn't have a convenient way out, but that's rare. A redouble of 2C: is takeout. We play system on if their pass is forcing to a redouble, but system off otherwise.

If they redouble for business, pass is to play. System should definitely be off.

We play that after a double, the next double is takeout, usually showing exactly two cards in their suit. Others prefer that the first double is only semi-natural and just shows extra values. Discuss this with partner.

We play that after 1NT is doubled, we are in a force through 2S:. Some prefer to make this 2H:, because the force on 2H: usually leads to our contract of 2S:, whereas being forced vs. 2S: forces us to the three-level.

In response to 2C:, 2D: shows no or little preference. This is quite helpful if overcaller is 5-4. 2NT is a natural game try. Jumps are invitational. 3D: is to play. 2D: followed by 3D: is forcing.

In response to the transfers, all bad hands simply accept the transfer. New suits are natural and forward-going, but not 100% forcing. 2NT is a natural game try. Jump acceptances are invitational. Yes, there is no force. That probably ought to get changed.

In response to 2S: showing spades and a minor, 2NT is an artificial game try, asking for size and the minor. 3C: is pass or correct. 3S: is invitational.

Over 2NT, showing hearts and a minor, 3C: is pass or correct, 3D: is natural and forward-going, 3H: is to play, and 3S: is natural and forcing.

Overcaller's Rebids

Everything is pretty much natural; second bids show extra strength. One strangeness is that a transfer to a major followed by a minor shows a four-card major and a six-card minor.

Other

We do not play this method by passed hands. Instead, we play Woolsey.
Jeff Goldsmith, jeff@tintin.jpl.nasa.gov, Dec. 19, 1996