Fantastic lesson, very clear.

4H makes assuming S has at least 4 cards in each minor. Declarer plays 4 rounds of trump and you can discard a spade and a diamond, but the 3rd discard is the killer. Whichever minor you discard, declarer leads his honor in that suit and ducks. Then a ruff sets up a winner in that suit for trick 10. A line that depends only on S holding all the high cards is better. Declarer tries a diamond to the Q at trick 2, you win and play another diamond. Declarer wins the K, ruffs a diamond, and leads all his trumps but 1 ending with Kx spades, Qx clubs, and a trump in hand, and Ax clubs, a diamond, and two spades in dummy. S must keep 2 clubs, 2 spades, and the diamond. Declarer can now lead club to the A, ruff the diamond, and exit Qc, scoring Ks as trick 10. S may succeed by keeping the As alone along with 3 clubs.

Ian from Melb aus

After west redouble north should not bid with 3 points, then you know he dont have any points

Due to lack of Vulnerability in this match point board, I think perhaps a better auction, in this case, would have been: W N E S 1H 2D 3H - - - And although I would normally lead the 4th highest card away from the King in other similar situations, if you've deducted that partner will be extremely weak in points-due to the outcome of the auction, you may have to reconsider. However, in auctions where it is likely partner DOES have a few points (e.g. 10+), then I don't see anything wrong with leading your 4th highest card away from a King-unless you have a better option.

Not wild about a double with only three spades. Also not a fan of requiring 3 honours in a suit for an overcall. It seems that you really restrict your possibilities for competing. Also, if West's redouble doesn't show support for hearts, how does that square with his later game invite in hearts?