I think we should keep the long major as six in first and second seat. I don't think there's any advantage in retaining the 8-11/10-13 ranges. Because immediate action is inhibited by not knowing opener's suit, it pays to use the Multi as a first-strike weapon. Therefore the usual 5-11 range, the actual strength depending on position and mutual vulnerabilities is more appropriate.

We lose the advantage of lightening the load on 1-major we had with Fantunes Twos. But the single-suit option wasn't the main incentive, rather those hands that might be frozen out when 1M is overcalled with 2-minor. With that in mind I think there is an argument for retaining the 8-11/10-13 ranges for the Muiderberg 2H/2S - what do you think?

You have the Horton/van Cleeff book, 'The Mysterious Multi' I believe. (PDF available for review purposes.) I've taken a few things from there - a bit mix and match - but the ingredients are as I play with Mike Ash. Possibly we could lift the Muiderberg treatment (I quite like the Modern style).

Three-way 2D
-------------

a) Weak two in major, almost always six, 5-11 ATV
b) Balanced 24-25
c) Game force with 6+ diamonds and 4 cards in hearts or clubs.

The idea is that 2C - 2D; 3D allows responder a second negative of 3H, now opener's 3S is natural but that's the only suit lower than 3NT. Therefore primary diamonds and secondary hearts/clubs go via 2D. I accept that our use of the 'Heart Murmur' 2D/2H lessens that consideration but it's no bad thing to have a waiting bid after opener's 3D rebid, whether or not responder's first move was an artificial 2D or 2H. Also we might one day embrace the 2C = strong or weak 2D gadget...

Responses
---------

2H	Pass/correct
2S	P/C
2NT	Suit and range-ask
3C	Hearts
3D	Spades
3H	P/C
3S	Nat, INV
3NT	To play
4C	TRF to major
4D	Puppet to 4H
4H	P/C
4S	To play!

i) 2H/3H/4H are pass correct - as is 2S
ii) 2NT asks
iii) 3-minor/4-minor are artificial
iv) 3S/4S are natural
v) 3NT is natural

Memory rule: opener only ever names his suit when responder bids 2S or hearts at any level.

With good hands (strong NT+) the most common response is 4C. Use 2NT/3-minor when other-major or NTs is possible. 2NT also serves as an invitation when responder can invite in both majors (and therefore cannot risk 2H/S in case the auction ends there).

2D - 2H
-------

Pass    Weak hearts
2S      Weak spades (3H to play)
2NT     Strong balanced
3C      D+C
3D      D+H

2D - 2S
-------

Pass    Weak spades
2NT     Strong balanced
3C      D+C
3D      D+H / Weak hearts max (3S to play)
3H      Weak hearts min (3S to play)

2D - 2NT
--------

3C	Bad hand
3D/H	H/S, Non-min, good suit (3H/S forcing, shortage next?)
3S/NT	H/S, non-min, good hand (
4C/D/NT strong types

2D - 2NT
3C - 3D   "bid other major"
       3H    Pass/correct

2D - 3-minor
------------

Always constructive, typically used with good hands and 5-1 in the majors but potential to improvise (avoid opener's bad singleton). You can always play 3-either major, so 6-0/7-0 is possible.

Step responses, raise of minor (step-5) and above indicates striking opener's long major. First such bid is no shortage / shortage in named suit (NGF style). Opener's strong hands start at 4NT...

2D - 3C
3D      0/1 support (3H/S NF)
3H      2 support (3S NF)
3S      3 support
3NT     4 support
4C      5/6 support, no shortage / short club
4D      5/6 support, short diamond
4H      5/6 support, short spade

2D - 3D
3H      0/1 support (3S NF)
3S      2 support
3NT     3 support
4C      4 support
4D      5/6 support, no shortage / short diamond
4H      5/6 support, short heart
4S      5/6 support, short club

I think we should play cheapest bid asks for shortage after a 3+ rebid.

In competition
--------------

We switch off the constructive 3-minor (they become natural NF) but retain as far as possible,

i) 2NT as a constructive ask
ii) 4C as "bid by TRF"
iii) 4D puppet to 4H
iv) pass/correct raises
v) 3S as natural
vi) 3NT as natural

Additionally,

vii) Double is negative (to avoid inferring the wrong suit)
viii) Responder's 3-level cue is a stopper ask.
ix) Opener's cue in response to any action is a strong type
x) If responder passes opener bids strong types naturally

After double, although H/vC suggest using a 'parking lot redouble' to get out in responder's own suit, I'm not a fan of that here. My favoured treatment allows opener to bid a fit suit if advancer bids 3-minor.

Pass = diamonds
XX = 'name your suit'
2H = P/C but compete in spades
2S = P/C but compete in hearts
2NT = (i)
3-minor = NF
3H = P/C

That's it, pretty much.

Chris