Transfers over Opponent's Takeout Double

We open with a natural or quasi-natrual bid at the 1 level (hereafter "1Op") and the opponents cheekily make a takeout double. We play all calls from XX to one below 2Op as transfers. Calls 2Op and higher are normal.

"Tg" refers to the suit being transfered to.

General Patterns

Competitive Only

Auction patterns which imply we are not interested in trying for game:

Transfer then Pass
Transfer to 1Tg, then a new bid ≤ 2Tg
Transfer to 1NT, then 2♣
1♦-(X)-1♠ALERT-2♣-2♦
When Op is a major, transfer then bid 2M

Game Invitational Patterns

Transfer to Tg, then bid 3Tg
Transfer then bid 2NT
When Op is a minor, bid 2NT directly
When Op is a major, transfer to 2Op then make a game try
When Op is a major, transfer to 1NT then bid 2Op

Game Forcing Patterns

Transfer to a suit then bid a new suit above 2Tg, showing 5+ of the first suit and 4+ of the second. (that is transfer to 2♦ then 2♠ is forcing, transfer to 1♠ then 3♦ is forcing, but transfer to 1♠ then 2♦ is non-forcing)
Transfer to 1NT then bid a suit (showing a one suiter, 6+)
When Op is a major, transfer to a new suit then bid 3M (implying 3 card support with a good holding in Tg)
When Op is a major, bid 2NT immediately (implying 4 card support)

Different Transfer Types

Transfer to a suit at the 1 Level

This shows 4+ cards in the target suit, and is treated effectively the same as a 1 level bid of that suit, including support doubles over Advancer's interference.

Assuming Advanced passes, Opener now bids "as though" Overcaller had passed and Responder had bid 1Tg except for two things. First, if Opener has three card support without extras, Opener bids 1Tg. Second, XYZ, New Minor Forcing, and other checkback systems are off.

Transfer to 1NT

The transfer to 1NT can be one of many things:

A hand that would have bid 1NT before transfers existed
Weak with both minors
Game Forcing with a one-suited hand
An invitational or game-forcing balanced hand that prefers not to declare NT.
A 3 card limit raise of Opener's major

So, for example, after 1♥-(X)-1♠ALERT-(P)-1NT-(P), Responder's next bid shows:

Pass - something like 7-10 balanced
2♣ALERT - weak with both minors
2♦ALERT - GF with one-suited diamonds
2♥ALERT - 3 card limit raise of hearts
2♠ALERT - GF with one-suited spades
2NT - natural balanced invite
3♣ALERT - GF with one-suited clubs
3NT - to play, but wanted to be dummy

Opener's Rebid

Opener bids as though Responder had bid a natural NF 1NT. If that call was "Pass" then Opener accepts the transfer with 1NT.

Transfer to a suit at the 2 level

The most common case is to show a "negative free bid" - a smattering of points and a 6 card suit or a strong 5 card suit. Over a major opener, it could just be a lead directing competitive raise to 2Op.

When Op was a major, we use 2Op directly to show a "bad" single raise and a transfer to 2Op to show a "good" single raise (and occasionally certain types of invitational hand). When Op was a minor, we use 2Op to show a michaels hand (55 majors) and 1♣-(X)-2♦ can just be weak with diamonds).

Responder's Rebid

2Op (Op=M) - 3 card limit raise
new suit (including Op when it's a minor) - GF two suited hand
3Tg - invite with good 6(+) suit
2NT - balanced invite; Opener's 3 level suit bid is sign off with more safety

Examples

1♦-(X)-1NTALERT-2♣-2♠	GF with 4+♠, 5+♣
1♦-(X)-1♠ALERT-1NT-3♣	GF with long clubs
1♠-(X)-2♣ALERT-2♦-3♠	GF with 5+♦, 3♠
1♠-(X)-2♣ALERT-2♦-3♦	inv with 6+ diamonds
1♠-(X)-XXALERT-1NT-2♦	GF with long diamonds
1♦-(X)-XXALERT-1♥ALERT-2♥	to play
1♦-(X)-XXALERT-1♥ALERT-2NT	balanced invite with only 4 hearts
1♦-(X)-XXALERT-1♥ALERT-3♥	invitational with 5+ hearts
1♦-(X)-2♥	same as 1♦-(P)-2♥
1♥-(X)-1♠ALERT-(X)-1NT	Minimum opener with a tenace in spades to protect
1♥-(X)-1♠ALERT-(X)-P	Minimum opener without a tenace in spades to protect
1♦-(X)-1♥ALERT-(2♣)-X	Support Double; 3 spades
1♠-(X)-XX-(P)-2♣	5+♥, 4+♣, NF
1♦-(X)-1♥ALERT-(P)-1♠ALERT-(P)-2♣	4♠, 5+♣, NF
1♦-(X)-1♥ALERT-(P)-1NT-(P)-2♣	4-5♠, 4+♣, NF

Penalty Redoubles

Sometimes Partner opens, RHO doubles, and you have some 11-12 count that feels like a misfit and it looks better to try to get the opponents for a number in a doubled contract rather than try for a dodgy game. Classically Redouble is used to show that sort of hand, to let Opener in on the news that we have points and that we are interested in making a penalty double. Here, however, Redouble is always used to make a transfer.

The solution here is to make a trap pass, and both partners can now reopen with takeout doubles. This is not as clean as "redouble starts penalty doubles" because Opener might not have suitable shape or strength to find a takeout double, however note that Advancer (Doubler's partner) is under more pressure than after a Redouble because they no longer have "Pass" as an option to indicate no particular suit preference.