A Reverse is a forcing bid by the opener. It gives partner a choice of two suits. If partner chooses one of the two suits, which shows minimum 6 or 7 points, he must do so at the three-level because a pass is not an option.
As a result, opener should have at least an ace above opening. In fact, 17 or 18 points are recommended. The first, lower ranking suit, is always longer than the second suit that is bid at the two-level.
Everybody has a reverse in their arsenal. Some may not realize they need a stronger hand.
South, with 17 high card points, opens one club, his longest suit. North will bid his suits up the line except when he has a five-card suit. North bids hearts, his five-card suit. South, with enough points to reverse, bids two diamonds.
North has to bid. Pass is not an option so he picks diamonds by bidding three diamonds. Either three clubs or three diamonds shows a minimum. South is not deterred and bids an aggressive five diamonds.
The contract: Five diamonds by South
The opening lead: The ace of spades
I do not like the lead. A club lead is the worst because it is declarer’s second suit. The others are not much better. A diamond lead may help the declarer bring home the trump suit. A heart lead is the opponent’s suit so it may set up that side suit. Leading an ace without waiting to capture an honour is not so good either.
The spade lead is the unbid suit and is the best of terrible leads.
Leading trump or leading dummy’s suit should only be done because there is a reason to do so not because there is nothing else to lead.
Declarer ruffs the ace of spades and recognizes the fact he cannot let East get in to lead hearts because of the king of hearts. The opening lead solved the problem and a heart goes on the king of spades.
Declarer ruffs a club and finesses the second round of diamonds which is won by West.
Declarer loses a diamond and a heart making his contract.
The result: Five diamonds making for +400
Note: It is good practice to control which hand gets in. With a sure trump loser, it is often better to play the ace of trump and then finesse a trump rather than playing the ace and king.