Invisible Cuebids, Splinters, and Doubles
This is an extension of "Unusual vs Unusual." These can be used
as a defense against any known two-suited overcall (say Michael's).
The invisible cue bids work as follows:
Bidding the lower known suit: 10+ hcp, support for partner
Bidding the higher known suit: 10+ hcp, showing the "4th" suit
The invisible splinters are:
Jumping in the other suits: 10+ hcp, splinter w/ support
*Bidding the 4th suit: 10+ hcp, splinter w/ support
[note: some may not want to play this as a splinter]
An extension of this is:
Direct raise of partner: up to bad 9 hcp, support
Game raise of partner: 8-9 hcp, good shape
Directly doubling: 10+ hcp, good defense of their suits
pass then double: you could only double one of their suits
pass then raise: up to bad 9 hcp, support, you might have doubled the other suit