A Positive Illustration

Here is a positive illustration of a defender handling four-card suits from the Scheinwold-Stewart column given on OKbridge:

8
Q 4 3
A K Q 7 3
9 8 6 2
A K Q J 6 5 3 9
5 8 7 6 2
8 4 J 10 6 2
7 5 3 Q J 10 4
10 7 4 2
A K J 10 9
9 5
A K

Against 6 hearts, West began with the king of spades and continued with the ace, which declarer ruffed high in dummy and East underruffed! East was given the name Minnie Bottoms. Declarer was Cy the Cynic, who thinks Ms Bottoms underruffed because she was befuddled, didn't hear well and thought he'd called for a low trump at trick two.
Of course the column was written with tongue-in-cheek, the point being that East had in underruffing made the only play that beats the contract. Keep the same number as dummy holds if you possibly can, I have often exhorted the reader. Here dummy has one more diamond than East, but that's hardly less reason for holding onto four diamonds. On the third round of trump, declarer will sluff a non-functional fifth diamond as East follows suit. Now East matches dummy's four-card holding . . . and on the next round of trump, declarer must make a discard from dummy before East. Ergo, no slam, as East keeps the same cards in each suit as dummy does.
Had Ms Bottoms discarded a minor suit at trick two, figuring you're supposed to keep trump, aren't you?, she would in effect have squeezed herself. If a diamond, you can see that the suit will run, and if a club, declarer can make hay with that: cash A K (when trump are out), a diamond to dummy, ruff a club, last trump, sluffing last low diamond and dummy is now good.
The writers didn't refer to "four-card suits", for after all, the reader can see how long they are. But that's what it's all about, watching those four-card suits. Not bad for a supposedly befuddled old woman. But there was one thing I took note of: They didn't tell us whether the lady ruffed with the deuce or the six (allegedly thinking declarer had called for a low trump). If she ruffed with the 6, then Cy the Cynic might well suspect that she didn't know what she was doing and did think he called for a low trump. But if she ruffed with the deuce, then it would have been obvious that she knew what she was doing and hardly thought she was overruffing. But of course, if they'd told us, it might have ruined a good story.