Hand 1.
Better stick that JD on the table NOW! Given this dummy, you really need three diamond tricks to defeat the contract and if partner has the A, and if you lead spcifically the J ypu will get them. What can declarer do?If declarer plays low, you can continue with the K and a diamond. If declarer plays the Q, partner wins and returns a D through the 10 which you are hovering over with K9. Curtains for declarer. Notice that if you dont shift to a D, one of dummy's diamonds goes off on declarers KH.
THE BOTTOM LINE
Leading the J from KJ9 or AJ9 combination when the dummy to the right has the 10 is called a 'surrounding play'. It can't lose a trick but it can gain when partner has the A or K and declarer the Q.

Hand 2.
Play the 4th club! Give declarer a ruff and sluff! Why?
If you count HCP and give declarer the least he can possibly have which is 15, partnerhas 2 at the most. Those 2 must be in spades. If partner has Q9x, a fourth club by you actually promotes that 9S to the setting trick. What can declarer do?
If he discards, partner ruffs with the 9S driving out the A and promoting the QS to the setting trick. If declarer ruffs with the 10 J or K , partner discards and Q9x of trump is now a natural trump trick.
THE BOTTOM LINE
When there are no possible tricks coming from the side suits, consider giving declarer aruff and a sluff which might promote a trump trick for partner.
Get into the habit of adding dummy's HCP to yours and declarer's HCP and subtract from 40 to find outwhat you and partner are working with. When things look desperate ( strong looking dummy ). assign declarer the least he can have for his bid and start working from there.
Marks Hand1 Hand2

Frazer 10 0
philip 10 0
Ben 6 0
Myles 10 0
Harold 10 0
David 6 0
Gordon 10 0
Andrew 10 0
Kirsten 6 0
Gyles 6 0
Douglas 10 10
Ronald -5 0
Alex -5 0


Better luck this week well done Douglas

Pardon me if I'm being stupid, but if declarer has 15 points, dummy has 10 and you have 8 does that not give your partner 7 and hence 3 remaining at most?

Furthermore, does giving a ruff and discard not give away the contract if declarer has, say:

KQJx
Qx
AKxx
xxx

which is a highly probable holding for his 1NT opening. (heart discard from hand -> 4 trumps, 3 diamonds, 1 heart, and 1 diamond and 1 club ruff)

if partner has Qxx of spades, there must be a close to 50% chance declarer will get the spade finesse wrong anyway.

Perhaps a ruff and discard may still be a better line but I dont think your explanation is correct on the hand. It is certainly not the case that "there are no possible winners coming from any of the side suits". Can you look at it again and repost a revised explanation - especially as EVERYONE except the mighty Doug got it wrong?

Thanks

i don't see why p cannot have the KH, as p can still have 2-3 points in which case a ruff and sluff gives the contract potentially. In my opinion, better to exit safely and hope declarer guesses wrong in spades or partner has KH.

Did You all forget that your partner lead the AC????????
Full hand, sorry I forgot to put it in
West: S.Q92 H.9753 D. 10862 C.A3
Declarers: S.KJ108 H. KQ4 D. AK5 C. 654.
It is imprtant to envisage what you NEED your partner to have to defeat the contract. Given that he has very little left a ruff anf sluff looks best bet. Try and envisage the hands. If pd has KH and not QS then it is going nowhere, but this is your last chance to do something if it is a spade holding pd has

Of course you remembered that pd lead AC!!
If Declarer has hand you suggested David, then pd must have xxx, Kxxxx,xxx,Ax
He discarded a D on 3rd club and can throw another D on 4th club
Declarer must ruff cl in dummy so that he can discard H, but also needs toruff 4th D in dummy,,, cant do and draw trumps. If pd has H. Kxxx and declarer Qxx then H trick still not going anywhere,as far as I cn see only problem hand that declarer can have is S.KQJx H.Kxx D. AKx C.xxx when a ruff and sluff will give contract, as will switching to a H .
Hope this helps, but I am pleased that you are thinking