CHAOS is invented in 2012, based on the idea of null-opening 1♣.
It is a very memory-efficient and chance-efficient relay system.
It requires very few "true memory" owing to its symmetric and deductive relay structure.
It maximizes the chance that an exact shape relay can be completed by "supplying" points to the (re-)opener during relay.
1♣=15+ waiting null-opening (responses similar to openings below with point range shifted, 1♠ and 1NT swapped)
Openings below listed from high to low priority:
1♦=11+ 5+♥s(or 4♥s,0-4♠s with singleton/void)
1♥=11+ 5+♠s
1♠=11-17 4♠s(or 3♠s with singleton/void)
2♣=11-14 6+♣s or 5+♣s;5+♦s
2♦=11-14 6+♦s with singleton/void or ♦ preempt
1NT=11-14 bal (catch all)
Step 1 responses of the openings are relay initiators, but as exceptions, step 2 responses are used for 1♠ and 1NT.
The reason is non-forcing 1NT to 1♠ and puppet 2♣ to 1NT provide good partial contract stops. Inventory FolderA Half-Page SummaryDownload System Detail(.xlsx)
In 2014, the 2WS is revised to fit the We-Only vulnerability.
The incentive is from that strong clubs are too fragile after interference while Fantunes narrows the space to find major games from a good 2-suiter shape.
This system has no weak preemptive opening.
1-suiters are required to start from 2M or 3m.
2-suiters are highlighted and are shown systematically.
The weak-or-strong 1♣ open reduces the incentive and effect of interference.
The 2-suiter only 1♦ strong open uses penalty doubles to bid own hands and maintains high risk for opponents' preempts.
1♣=12-14 bal/17+ 1-suiter/18+ 3-suiter/18+ bal
1♦=14+ 2-suiter
1♥=4+♠s 10-13 2-suiter or 14-17 3-suiter
1♠=10-13 2-suiter with 5+♥s or 14-17 3-suiter short ♠
