HERE'S A COUPLE OF CHESS EXPERTS YOU CAN KEEP IN YOUR HIP POCKET

Only a few years ago a machine smart enough to play a decent chess game would fill an entire room. Later, scaled-down models began appearing in upscale toy stores. Now the latest marvels of miniaturization are chess computers so small they'll fit in a pocket or palm.

Two new mini-sized models, Mattel Electronics' Computer Chess and SciSys (pronounced SIGH-sis) Computer Inc.'s Executive Chess, are especially portable and compact because they don't use conventional chess pieces at all. Both have 3" x 3" liquid-crystal display (LCD) screens divided into 64 tiny squares. A push of the start button on either model fills its screen with symbols for each of the pieces in the starting position, and either the player or the computer can open the game. The player makes a move by placing the computer's cursor over the piece he wants moved, pressing a button to attract the computer's attention, moving his cursor to the destination square and pressing "enter."

The Mattel model plays at four skill levels, producing almost immediate replies at Level 1 and consuming up to 30 minutes per move at Level 4 because it "thinks" further ahead. The SciSys device has eight skill levels.

On both machines, a player can set up chess problems by electronically placing pieces wherever he wishes. Mattel's game also allows two humans to use it as a conventional chessboard. An option offered by both machines is to have the computer play both sides at once.

Computer Chess, which runs on four AA batteries (there's an inlet for a six-volt AC adapter but, oddly, none is provided or offered), sells for $130. Executive Chess runs on six AA's and comes with an AC adapter for $129.50.

How smart are these little computers? Well, neither purports to be capable of beating its bulkier big brothers—or human grandmasters, for that matter. They do, however, provide a stiff challenge to intermediate players and wallop beginners with ease.