[luis]

Hi everybody.
Soon World Class players and some lucky others (hope to get in) will play a rematch of the "Naturalists vrs Scientists" classic.
This time Scientists will use "Moscito" a relay system based on 4 card majors that was created by Paul Marston (Australia). A german team leaded by Rene Stainer created a version and GIB (the leading computer bridge software) played a version called Moscito-Byte to win the computers bridge championship many times.
I'm not a super-expert but I'll try to introduce the ideas in Moscito and present some of its flavours.

MOSCITO (Majors-Oriented-Strong-Club = MOSC) is a system based in a strong club opening and 4 card majors. The system tries to open as many hands as it can to get into the auction frequently trying to find if possible a major suit fit at the safest level as soon as posible.
Light openings are the key to the system, the "oldets" version of Moscito used 10-14 openings and the modern variations tend to allow 8-14 openings where 8/9 HCP hands with good distribution are opened (Example 5431 hands). This means that almost all 10HCP hands are opened by rule.

The opening bids depend on the "flavour" of moscito being used, some variations are:

a) Modern variation
1c = 15+ any
1d = 9-14 with 4+ hearts
1h = 9-14 with 4+ spades
1s = 9-14 with 4+ diammonds
1N = 12-14 balanced without 4M

Modern variation b
Same as before but 1s can be any unbalanced hand without 4M

c) German variation (this is almost natural and ACBL compliant)
1c = 15+ any
1d = 10-14 no 4M
1h = 10-14 4+ hearts
1s = 10-14 unbalanced with 4+spades
1N = 10-14 balanced with 4 or 5 spades
2c = 10-14 5+/4+ or 4+/5+ in the majors

Two level openings depend on the pair playing Moscito and the version being played.

Once the bidding starts Moscito uses "relays" to find out the distribution, controls and location of honors in pd's hands, the relay principle stablishes that one hand "asks" while the other "describes", if the hand being describe ends being the dummy the defense is blind with zero information about declarer's hand. If the inverse occurs: delcarer hand being known then you are playing an open hand.

Most versions convey that a relay shows an invitational or better hand and a second relay is game-forcing. Thus Moscito is in GF situations at very low levels of the bidding so forcing passes are very frequently and penalty doubles start very early (if GF then passes are forcing and dbls are for penalties usually). Moscito can describe accurately almost any hand from the common 4-4-3-2 patterns to the wild 8-2-2-1 patterns. You just have to learn the proper structures to use in relay sequences.
Denial cuebids and asking bids are used after the distribution is know to get the number of controls and specific location of honors to know if you have to play game, slam or a grand.

Luis

[Laird]

Hello Luis

Thank you for that smashing summary of the Moscito system it is most helpful.
As a traditional Acol player if someone could do a similar summary regarding 2/1 and Fred's proposed strategy for playing against it, that too would be helpful as both systems are a bit 'foreign' to me.
I'm sure that by keeping beginners and intermediates informed in this way then it will help to break down some of the mystery or fear associated with playing against those who play 'moscito' and may in time allow it to be more generally acceptable.

Kind regards
John

[luis]

2/1 is based in the idea that a 2 over 1 bid is forcing to game.
Examples: 1s-2c; 1s-2d; 1s-2h; 1h-2c; 2h-2d.
Some players also agree that 1d-2c is forcing to game but this treatment is not universal.

Some players play that a 2/1 response is an absolute game force, others play that a rebid of the 2/1 suit is non-forcing (example: 1s-2c;2d-3c). So as usual there're many "flavours" of 2/1

2/1 uses 5 card majors, with a specialized "forcing" 1nt response as a catch-all of non-game forcing hands without support.

The 1M-2NT response is generally used to show 4 card support and INV+ values, using Jacoby, Stemberg or something similar.
So the 1M-1NT (forcing) response normally encloses:
- Weak signoffs
- Limit raises with exactly 3 card support
- Balanced hands with invitational values

Bergen raises are frequently used to complete the major-raises structure.

Some players play 1NT forcing even in a passed hand, others don't (more to agree). Some players also reverse the meaning of 1s and 1NT when opening 1h:
1s = A forcing 1NT bid
1N = 5+ spades and forcing.
This treatment allows the 1h opener to rebid 1N with a balanced hand so you can play 1N when opening 1h.

An inmediate side effect of 2/1 is that you can't play 1NT when you open 1 spade.

The 2/1 sequences have variations too, the most used principle is "fast-arrival". Once you are in a game-forcing situation use cheap bids with powerful hands to get more bidding room and explore slam chances and blast to game with minimum hands.

Example:
Kxx, xx, AKxxx, Qxx (1s-2d; 2x-4s) Describind a minimum hand with diammonds and 3 card support for spades.

After a 2/1 response opener rebids are:
Support pd suit with Hxx or 4 cards (only)
Bid a new suit at the 2 level with 4+ cards
Bid a new suit at the 3 level only with extra values
Bid 2NT with stopeers in both unbid suits

So opener frequently rebids 2M even with 5 cards if none of the above rules apply.

It's very hard to describe 2/1 since there're many variations and posible agreements.

Hope this helps.

[hrothgar]

Hi John

I have posted a very complete convention card describing my preferred MOSCITO variant at http://web.mit.edu/~...www/MOSCITO.htm

One "feature" that I included in the convention card is a set of sugested defenses to the more unusual openings. For example, if you drill down to the detailed description of the 2D opening, you'll find a suggested defense. Alternatively, you can get there directly via

http://web.mit.edu/~rwilley/www/MOSCITO.ht...DiamondsDefense

[the hog]

a) Modern variation
1c = 15+ any
1d = 9-14 with 4+ hearts
1h = 9-14 with 4+ spades
1s = 9-14 with 4+ diammonds
1N = 12-14 balanced without 4M

In the latest versions 1S is unbalanced with 4+D. 1NT can certainly have a 4 card M and is 12(11) - 14.
What most characterises the latest version is the realisation that the 1C 1D (neg) response occurred too often. To optimise responses:

1C 1D = most game forces
1H = 6-9 semi pos (sp) with H or balanced or any 4441
1S = garbage 0-5
1NT = sp with S
2C = sp with C
2D = sp with D
2H/S = sp 4 in that M and Ds
2NT = 10+ with 5440 with a Major suit void.