Guam -- rusting tanks, coral strands, and 80 deg water

It's a soft Pacific night -- damp, with wisps of fog and cloud around us. And it's blue-black dark between the lights of the DC-10 and those of Los Angeles disappearing beneath the plane's belly.

It has been dark for five hours by flight time. it will be dark for some 14 hours to come.

The DC-10 noses its way west from California at about 400 miles an hour. The sun chases it at over 900 m.p.h. but, even so, it is all the way to Guam before the sun gains enough strength to lighten the sky appreciably.

That seems fitting, since Guam bills itself as the place "where america s day begins."

Californians are some 5,000 miles across the Pacific from home here. But they are in the US territory. It has been under US rule since 1898.

At eight miles wide by 32 miles long, this is the largest land mass between Hawaii and the Philippines, yet if it's known by mainland Americans at all, it's probably for one of two reasons: Guam is the home of the Strategic Air Command's Andersen Air Force Base, and it is a quick and, it seems, always-very-early morning fuel stop on trans-Pacific flights.

Some 85 planes arrive each week at Guam's international air terminal. But it is only recently that the passengers on those flights have thought to stopping over.

Just a decade ago, Guam saw few tourists. In fact, there wasstock in trade.

Today, there are resort facilities the equal of those found everywhere. There is a hilton here and several fine Japanese hotels -- the Guam Okura, the Guam Fujita, and the Guam Dai-ichi, all fronting on Tumon Bay.

There is good reason for the deluxe Japanese accommodations. Most of Guam's tourists are Japanese; the island is just three hours by air from Tokyo, and this is a popular honeymoon resort for them. But increasing numbers of US traveles are discovering the island, too.

Not that Guam will ever replace, say, Hawaii, as a prime Pacific destinatin, but it does have something to offer travelers who would like to break up the long flight between the West Coast and the Orient.

For instance, there is year-round summer. The air temperatur is in the tropical range, and the water is a clear and pleasant 80 degrees. It sluices over the kinds of coral formations that sing siren songs to scuba and skin divers. There are guides available, and several dive shops on the island rent equipment.

If warm white sand is your Lorelei, you will find it along Tumon Bay (handy to the resort hotels), Agana Bay, Agat Bay, Gun Beach. These are the best beaches for shellers, too, although some of the lagoons are worth scouring as well, especially the one between Merio and Cocos Island.

Actually, Merizo, the tiny Chamorro village at the southern tip of Guam, is proably your best water-sports base. You will find boats for coastal sightseeing (including glass- bottom ones for viewing coral gardens) waterskiing , fishing. You can also hire one to take you to Cocos Island for some isolated picknicking and sunbathing.

Guam, because it is so new to tourism, has many solitary spots for sunbathing and swimming. Pacific Safari (PO Box 6840, Tamuning, Guam 96911) will help you get to them overland. They offer off-the-beatentrack charters for $100 for a half-day jaunt. For $30 or so, Pacific Safari will also help you explore Guam's World War Ii past. Their jeep expeditions take about five hours; they wind pas trusing tanks and other war machines and through the island's jungle to areas where land and sea battles took place.

One of the more intereisting treks is to the cave home of Shoichi Yokio; it's a lesson in survival.

Yokio, you might recall, fled the US troops who recaptured Guam from the Japanese in 1944. He did out on the island for 26 years befor admitting defeat. During that time, he lived in a cave so small today's visitors generally have to crawl through what was his living and cooking area. And he used the materials readily available for his household comforts: coconut oil for lamps, the fibers for rope. The coconuts themselves are containers. He cut a canteen into a frying pan; shaved bamboo for needles, and handwove clothing.

Most of the things recovered from the cave wergovernments, and many of those going to the US can be seen in the Guam Museum in Agana.

There's not a lot of what can strictly be called "sightseeing" one can do in Agana. The buildings mainly have been reconstructed since the war and don't have the Spanish charm of, say, Umatac, the picturesque village said to be the place where Magellan landed in the 1500s. But you can tour the museum and Latte Stone Park, a monument to an ancient civilization whose only traces are rough-hewn columns of coral rock.

You can also shop. It may seem strange, but tiny, out-of-the-way Guam rivals Hong Kong and Singapore in price and selection of goods. You'll find Gucci here and Fendi and Catherine of Paris. There are also shops offering handicrafts, pearls, and fabrics from Micronesia, and cameras and electronic goods from Japan.

And there is an added advantage: US residents get a $600 duty-free allowance on goods purchased here when clearing customs at home. That's double the amount available at the Far East shopping meccas.

You can stop off on Guam at no extra charge on trans-Pacific flights from either direction. To take full advantage of the dutyfree shopping, though, the best time to do is eastbound -- that is, on the return trip. If your flight works out the way mine generally do and you begin your day when America's day begins . . . well, think of it this way: You'll have that much more time to shop.