I was playing with my friend, a bright beginner.
The double by West (an elder very strong national player) showed a 1-suiter.
When dummy came down I regretted pard did not decide to look for a penalty at favourable vuln, but my pard was not used to handle conventional bidding, so he preferred a practical bid rather than look for something fancy (e.g. he did not know what a redouble or pass then double would mean).
The lead was small diamond (attitude lead, says nothing of suit length), and East played the Ten.
How do you play to make ?
E.....S.....W.....N
p....1NT...X(1).3NT
all pass