Know what bids mean over interference

One weakness of a strong club system is how prone it is to interference.  I was East and held:

W

Pard

♠

xx

♥

Q109

♦

AQx

♣

KJxxx

Lead: ♥6

E

Me

♠

KQJx

♥

KJx

♦

Kx

♣

AQxx

The bidding went:

W

West

N

North

E

East

S

South

—

Pass

1♣¹

2♦²

2NT³

Pass

3♣⁴

Pass

6♣

All Pass

(1) 16+, artificial

(2) weak

(3) 8-12, balanced, diamonds stopped

(4) Undiscussed territory

I meant the 3C as Stayman, but partner thought that (a) I had clubs and (b) I had extras, something like 21+ points.  He wasn't sure what 4C or 4NT would have been, so he just bid what he thought we could make.

South led a low heart.  North cashed his two aces and then, to add injury to insult, returned a heart for a ruff.  6C down 2 when the field was in 3NT making 5 was a cold bottom.

This hand illustrates once again (a) the importance of having firm understandings after interference over a strong club opening and (b) not torturing partner with undiscussed bidding sequences.

On the other hand, we got a cold top for bidding this heart game, thanks to a very informative Precision 2C opening and even more informative spade overcall:

W

Pard

♠

xxx

♥

AKxx

♦

x

♣

AQJxx

Lead: ♠4

E

Me

♠

x

♥

QJxx

♦

xxx

♣

K10xxx

The bidding went:

W

West

N

North

E

East

S

South

—

—

—

Pass

2♣¹

2♠

Dbl²

Pass

4♥

All Pass

(1) 5-4 in clubs+major or 6+ clubs, 10-15 points

(2) negative double (hearts)

With the spade overcall, I was able to visualize a double fit in hearts and clubs and a singleton diamond in partner's hand to go with the singleton spade in mine.  I doubled and was happy to see partner raise to 4H with a maximum (14 points, in context) and good shape.  Even though hearts broke 4-1, partner was able to lose a spade, a diamond and a heart to make the contract.

It turns out that North had a two-suiter in diamonds and spades and nearly all the missing points. Over 2C, they had no agreement on how to show this specific two-suiter and once it came back, the five-level was too high to show diamonds. Had they been playing Leaping Michaels, 4D would have been game forcing, showing diamonds and a major, but as far as I know, no pair in the Norman club game plays it ...

Partner and I ended the evening with 70% -- a long while since I've had one of those