Because of its leadership position, the defender owns a strong point in the mind of the prospect. The best way to improve your position is by constantly attacking it. In other words, you strengthen your position by introducing new products or services that obsolete your existing ones.

IBM is a master of the game. Every so often, IBM introduces a new line of mainframe computers with significant price/performance advantages over existing products.

Competition continually struggles trying to catch up. A moving target is harder to hit than a stationary one.

Gillette is another example. Gillette owned the wet-shaving market with a product called the Blue Blade and subsequently the Super Blue Blade.

The company was stunned when rival Wilkinson Sword beat it to the market in the early sixties with the stainless blade. Then in 1970 Wilkinson Sword followed with the bonded blade, a metal blade fused to plastic at the optimum shaving angle. At that point Gillette got its act together and started to play a brilliant game of defensive warfare.

Shortly thereafter Gillette counterattacked with Trac II, the worlds first double-bladed razor. The success of Trac II set the pattern for future Gillette strategy. Two blades are better than one, said Gillettes advertising.

Better than one Super Blue Blade, said the companys customer who promptly bought the new product instead of the old. (Its better to take business away from yourself than have someone else do it for you.)

Six years later, the company introduced Atra, the first adjustable double-bladed razor. Again, by implication the new product was better than the Trac II, the nonadjustable two-bladed razor.

Nor did Gillette hesitate to introduce Good News, an inexpensive disposable razor (with two blades, no less). This was an obvious attack against Bic, who was preparing to introduce its own disposable razor.

Good News was not good news for Gillette stockholders. The disposable cost more to make and sold for less than Gillettes refillable cost more to make and sold for less than an Atra or Trac II was costing Gillette money.

But Good News was good marketing strategy. It blocked Bic from running away with the disposable portion of the market. Furthermore, Bic paid dearly for its modest share. Trade sources say Bic lost $25 million in its first 3 years in the disposable razor business.

Gillette continues its relentless strategy of attacking itself. Recently it introduced Pivot, the first adjustable disposable. This time, its own Good News product is the target.

Gillette has gradually increased its share of the wet-shaving market. Today it has some 65 percent of the business.

Attacking yourself may sacrifice short-term profits, but it has one fundamental benefit. It protects market share, the ultimate weapon in any marketing battle.

The reverse is also true. Any company that hesitates to attack itself usually loses market share and ultimately market leadership.