An alternative was to bid five diamonds, to show where his side strength lay.

As it turns out, I was wrong to bid two diamonds.

If they did, South would consider bidding four diamonds, knowing about the 10-card fit and remembering the law.

Notice that South was right, up to a point, to bid six diamonds.

If East began with 2-5-5-1 distribution he might have bid five diamonds.

Whether West should have bid five diamonds rather than four is debatable.

When his partner opened one spade, South's first thought was to bid two diamonds.

With a strong raise he would have bid three diamonds.

If a suit is forcing, North can afford to bid two diamonds.

North had every reason to bid six diamonds, which might have been easy.