[Liversidge]

Can someone explain to a novice the pro's and con's of leading the Ace or the King with an AK doubleton vs. a suit contract.

[wank]

it matters not a lot. in ye olde-fashionede bridge the ace was the standard lead from AK and king followed by ace was used to indicate a doubleton (and hence highlight that you wanted to ruff later).

[NickRW]

wank, on 2016-October-20, 00:59, said:

it matters not a lot...

I wish I had AK doubleton on lead more often for it to matter!

When you have AK doubleton on lead and p has a quick enough entry that you can get him/her in to lead before trumps are drawn, a lot of the time your side was strong enough that it should have been playing the contract in the first place.

[Stephen Tu]

From AK doubleton you lead the opposite card of what you normally lead from AK with additional cards. Then partner will know you have a doubleton, and should try to send a suit preference card on the second trick, then hopefully get in and give you a ruff.

So there is really not a "pro or con" of leading one card or the other as it's simply the opposite of what you do with AKx. The real pros and cons have to deal with which card to lead from AK with small cards, which comes up far more often than the AK doubleton situation.
There's a bunch of possible agreements:
1. A from AKx. Fairly popular these days. Pro: no ambiguity on the K lead, partner with the J can encourage. If declarer holds up the ace can then continue without fear of leading into AJx. Con: if leading the bare ace, partner will assume AKx and you won't get an accurate signal. Which is why most advanced pairs with this agreement make a bunch of exceptions for situations where leading a bare ace is more attractive than normal, like against high level (5+) contracts, high preempts, partner's suit etc.
Also: DO NOT USE in the middle of the hand, after trick 1. This is because leading bare aces is necessary a lot more often than on opening lead and an accurate signal is necessary.

2. K from AKx and also KQ(x). Older style. Pro: ace now denies the K (unless AK doubleton), so will get an accurate signal when leading from ace alone. Con: K is now ambiguous, if the ace/Q not visible third hand can't encourage holding just the J since he has to assume AKT and not want to let declarer's potential Qxx score. Then leader from KQx may not continue fearing declarer holding up with AJx.

3. Rusinow, 2nd from touching honors, so K from AKx, Q from KQx. But highest card first from doubleton honors. Pro: No ambiguity from either ace or king lead. Con: Doesn't work well when leading from Hx doubleton, or singleton for that matter, since partner will assume the higher touching honor. So at minimum need to play differently when leading partner's suit, may also discuss other exceptions. Applies trick 1 only.


There is also another style of A for attitude signal, K for count signal, though I would think this is not too conducive to being able to show AK doubleton.

[Tramticket]

So, to summarise the above:
- 1. Agree with partner what you will lead from AKX(X)(X). This is far more important than agreeing what you will do with AK doubleton (which is a rare holding). There are various options and different experts will favour different methods.
- 2. If you choose any of the three numbered options that Stephen has listed, you can use the opposite card to indicate a doubleton.
- 3. I'm guessing that these options are covered by what Wank calls "Ye Olde-Fashionede bridge". There is a further option to lead the Ace when you want partner to give an attitude signal and to lead the king when you want partner to give a count signal (or maybe to unblock in a no-trump contract). This is perhaps a newer idea, although it has been around for quite some time now. This loses the option to distinguish the lead of AK doubleton - but this isn't a great loss.