[goingoren]

♠ AKQ98
♥ Q5
♦ 7
♣ KQ843

bidding goes :

1s 3d 4c 4d 4s

opponents stay silent

[billw55]

What is your agreement with this partner about the meaning of the 3♦ bid?

[goingoren]

pick up partnership

[Zelandakh]

This is basically impossible to answer without having some idea of the level of the game. The normal meaning for the auction up to 4♦ is that you have shown extras and partner has a big one suited hand and insists on playing diamonds. In a good game you could choose to advance 4♠ as a cue bid but I would personally not choose to do that in this situation as the chances are that partner will play you for a 6♠-4♣ hand. I think both 5♣ and 5♦ are more practical continuations although I would be concerned that partner will not realise that I have extras and consider something more. Again, a feeling for the abilities of partner are useful here. If they really have their bid then we have good chances of slam...but whether to trust them on that is another matter entirely.

[gszes]

Difficult to imagine a hand where p bids 4d and it is right for us to bid further. 3d had to be PJR (if that was possible given the info given on they avatar box).

[billw55]

In a pickup partnership, with 3♦ undiscussed, you are pretty much just guessing. Partner's hand could be weak, strong, or invitational, depending on his own ideas. Maybe it was a conventional spade raise, and he thinks 4♣ and 4♦ are controls. Take your best guess and don't worry about it too much. I assume that you checked his profile and that was no help.

Partner is likely to insist that the way he meant it is the only correct way to play it, and perhaps to insult you over it. Don't worry much about that either.

[ArtK78]

Without prior discussion, 3♦ should be a strong jump shift. I am assuming that there is nothing in the player's profile about Bergen, WJS, or something else.

So, over 4♦, which should show solid diamonds, I BW and bid to the appropriate level (I hope we have at least discussed whether we play key card or not). If no aces are missing, I bid 7NT.

This could be spectacularly wrong, but that is the price you pay for not having any agreements. And, in the case of your partner, that is the price that you pay for springing an undiscussed bid on partner.

[1eyedjack]

Without prior discussion, I would simply not bid 3D. Ever. So you did fine, whatever happened.