Myxomatosis Two Bids
I found the explanation of these bids at an excellent site created by Chris Ryall, which you can fit at http://www.cavendish.demon.co.uk/bridge.
This is a 2 system developed quite a few years ago by Bob Sebesfi (also of SWINE 1NT escape fame)
2C = Game Force or Weak 2D or 5/5 H/S with 5-10 HCP
2D= Strong 2D or Weak 2 H or 5/5 S/C 5-10 or 21-22 balanced
2H = Strong 2H or Weak 2S or 5C/5D 5-10 HCP
2S = Strong 2S or Weak 3C in or 5D/5H 5-10 HCP
2NT = 5/5 / or / 5-10
3C to 3H: Transfer preempts
3 S= Gambling 3NT transfer (right sided for once)
3NT:Minor suit preempt to 4 level. 4C/D are SA Texas
Response 2NT force over the Two bids, 3H over 2NT
Variant A Correspondent, Sean Bentley modified this with all four strong two's (including 2) 8½ tricks but not game forcing, and to include 20-27 balanced hands in 2 point bands into the two bids. He also plays the 5-5 hands as either weak or game forcing (jump?) and to top off the 27+ NT hands, also in bands.
2C = 8½+ tricks in C.or. Weak 2D or. {5H/5S 5-10 / GF} .or. 21/22 bal .or. 29/30 bal
2D = 8½+ tricks in D.or. Weak 2 H.or. {5S/5C 5-10 / GF} .or. 23/24 bal .or. 31/32 bal
2H = 8½+ tricks in H or. Weak 2S .or. {5C/5D 5-10 / GF} .or. 25/26 bal .or. 33+ bal
2S = 8½+ tricks in .S or. Weak 3C .or. {5D/5H 5-10 / GF} .or. 27/28 bal
2NT = (5C/5H .or.5D/5S} {5-10 / game forcing}
In this approach the big hands are either treated as balanced (I might tweak the NT ranges), Acol Two bids or 5/5.
Variant B
2C = "forcing" inX .or. Weak 2D or. 17+ 4414 short D.or. 21/22 balanced.
... Over 2D you pass or bid 3C strong, 2NT=balanced, and 2H= short D
2D = "forcing" in D.or. Weak 2H .or. 17+ 4144 short 2H .or. 23/24 bal
2 H= "forcing" in H.or. Weak 2S .or. 17+ 1444 short in spades .or. 25/26 bal
2S = "forcing" in S.or. Weak 3C .or. 17+ 4441 short in clubs.or. 27+ bal
... Over 2D/H/S we have a similar but permutated set of responses
2NT = 5-9 5/5 in the minors (major or minor two suited also work