Among the purest golf swings on the PGA Tour, few can match the natural mechanics of Tommy Armour III. For basic instruction, his swing is one that offers the kind of uncomplicated lesson anyone can heed and benefit by.

Armour's art is a short backswing. Exceedingly short. On the takeaway, its arc is a little less than three-fourths of the average tour backswing, and about one-half the gyration of John Daly, the noted ripper.

I've long admired players with short backswings. Besides Armour, the list includes Doug Sanders, Homero Blancas, Lee Trevino, Dan Pohl and Tom Lehman. Why admire their swings? One reason: simplicity. If the shelves of pro shops were stacked with backswings, I'd advise the novice golfer to buy the shortest one. For high handicappers, as well as seasoned players, I'd suggest trading in the conventional swing--the one that goes to parallel on the backswing--and begin to simplify by going short.

The elongated backswing is the complicated backswing. Why have it? The golf swing is already an unnatural athletic motion that involves--as all chiropractors know--more than 60 muscles, each called upon to produce energy in less than one uncoiling second.

To renew my faith in the short backswing--not that it's been wavering--I followed Armour on the front nine in yesterday's opening round at TPC at Avenel. I caught him last year, also, during his final round when he was in the lead before fading near the end. Yesterday was the ideal moment to observe Armour's backswing.

With 39 strokes on the front nine, his score was certainly no distraction.

The compactness of Armour's swing illustrates the essential mechanical point: Nothing much happens in a long backswing that can't happen in a short one. Power at impact is generated by hand action coming toward the ball, not arm action going away from it.

Aside from practice tee conjecture among the swing doctors, little evidence exists that a full swing adds yardage. From Armour's drives yesterday, the opposite is true. On the 435-yard fourth hole, with Canada geese bobbing on the long pond to the left, Armour effortlessly crunched one more than 300 yards, leaving only a feathered 9-iron to the green. At the 359-yard fifth hole, he was a half-wedge short of the green. Consistently, he outdrove playing partners Emlyn Aubrey and Mike Hulbert by 20, 30 and, once, by 40 yards.

I wish more spectators had been following Armour yesterday. He has been on the PGA Tour since 1981 and has earned nearly $3 million in his career.

It's worth a forlorn wish, too, that the virtues of the short backswing would become obvious to more golfers. While watching the excessive and often wildly disjointed and loopy backswings of my occasional playing partners, I wonder which teaching pro should be sued for malpractice for instructing these hapless overswingers to take the club back so far--and ruining what are already futile chances of enjoying a decent shot.

For nostalgists, there's another reason to walk with Armour.

He's the grandson of Tommy Armour, the Silver Scot, of the Jones, Hagen and Sarazen era, and who won the U.S. Open in 1927. He died in 1968, when Tommy III was 9 years old and had yet to take up the game. In the late 1950s, the Silver Scot was an habitue of the grill room at Winged Foot Golf Club in Westchester County, N.Y., where his pal, Claude Harmon, was the pro. I recall seeing Armour there one late afternoon when, lubed with the national brew of his native Scotland, he sat at a corner table regaling the 19th holers with tales from his glory days.

Many of the stories can be found in his book, "A Round of Golf With Tommy Armour" (Simon & Shuster). One of its lines is on the art of the golf swing: "It is an awkward set of bodily contortions designed to produce a graceful result."

For a glimpse of those results at the Kemper Open, go a few holes with Tommy the grandson.

Colman McCarthy will be writing this week on how watching a golf tournament can help improve your game. McCarthy, a former Washington Post columnist, wrote "The Pleasures of the Game: The Theory-Free Guide to Golf". In 1959, he played in a PGA tournament--and made the cut.