Normal contracts were 4 Spades and 3NT from both sides, but I was surprised to get a 100% score in 3NT. I was South. I had done nothing special but see how the play develops.
The bidding had gone ONE DIAMOND - ONE SPADE - TWO CLUBS - THREE NOTRUMP.
T1: D 5, 8 ( I might have played the J) 9, won by K
T2: I played a diamond, West won and shifted to a heart.
T3: East won when I played small from dummy.
I now had +660. Everywhere else either spades were cashed first causing defense no particular trouble with discards, the order of developing H and D also making it easy for defense to cash their three winners (+630), or the hand was declared by north, when you dont get the friendly diamond lead (+630).
So, it seems that when I had just gone about developing additional diamond trick, I had unintentionally cut one defender off from another, given that West did not cash out. At the early stage, West could not know that a matchpoint cashout situation was in the offing.