Assign the Blame

Here's a bidding problem from the Reisinger. With both sides vulnerable you pick up:

South
AKQJ
xx
x
KJ10xxx

Partner opens 1, you bid 2, and partner splinters with 3. What call do you make?

The lack of a heart control is a mild flaw, but it's so likely that you have a slam—and perhaps a grand—that you choose to assume a heart control opposite and ask for keycards. You bid 4, Kickback, and partner responds 4, 0 or 3. What now?

Clearly partner would not splinter with no keycards, so you have all the keys. 7 should be (virtually) cold, but you can do better at board-a-match. If partner has a red-suit king, you will be nearly cold for 7NT, at worst having to guess who to play for a club void in case that suit is 3-0. You bid 5, asking for specific kings, and partner bids 6, showing no side king. And you?

Easy, 7. LHO doubles. Uh, what? Clearly you're having an accident. It goes all pass and lefty leads a low heart. Dummy comes down and you see:

North
QJ
AKQ98xx
Qxxx
South
AKQJ
xx
x
KJ10xxx

The defense take the AK and the A. Down three, -800. Unsurprisngly, you lose the board.

What happened? Partner had a momentary lapse and forgot that 4 was Kickback. He was just cuebidding his spade void.

When I discussed the hand later with my teammates, Bart Bramley and Kit Woolsey, Kit said that this was another loss for 1430 with Kickback. If partner's 4 response had shown 1 or 4, I would have just signed off in 5 and all would be well. We'd have been down one, presumably, but that would have pushed the board.

I disagreed, arguing that Kickback itself was at the root of this disaster. If my Blackwood bid had been 4NT, not 4, there would be no confusion. That a 4 1  or 4 response would have been able to avoid the disaster on this particular hand was just random.

So here's an unusual ATB problem for you. Which is at fault here, Kickback or 1430?

All 1430
Mostly 1430