the Reiyo Maru (heavy smoke, right), San Francisco Maru (on fire, centre) and Hoki Maru (light smoke, below) are hit

	Shonan Maru hit by shellfire from US destroyers;

	Marine flight crews

	Japanese officers arrive on Guam after the surrender.

	Clear waters and archetypal desert isles beckon.

	A blizzard of fish surround a diver on the Shinkoku Maru.

	The wreck of a Japanese Zero

	The Fujikawa Maru is full of interesting sights, large and small. Among the more everyday objects is a pile of beer bottles.

	Chuukese children at play on a shoreline wreck.

Feb 16, 1944, 6:30am, flight deck of the USS Enterprise

One by one the ship's complement of F6F Hellcat fighters roar down the strip of deck and clamber into the air. Operation Hailstone has begun. The scene is repeated on board the Yorktown, Essex, Intrepid and Bunker Hill as, in all, 72 Hellcats assemble in the air into three groups of 24 aircraft under the command of Commander William Kane. The pilots are charged with clearing the skies over the Pacific island of Chuuk of enemy fighters to leave the way open for the waves of Dauntless dive-bombers and Avenger torpedo-bombers to come. The bombers job is simple enough: to sink the Japanese ships and destroy military installations on the atoll. However, the US High Command is taking a gamble. Intelligence is almost non-existent: it is believed that no Westerner has even seen the atoll for 25 years. But faced with the horrifying price in lives paid for the amphibious landings used so far by the Allied forces in their effort to push the Japanese back to their homeland, new tactics are called for. Chuuk is about to be the scene of the biggest battle in the Pacific war so far.

One of the largest atolls in the Pacific, Chuuk is a clutch of 14 major islands and numerous islets and rocks, set at the heart of Micronesia. Encircled by a coral reef over 200km in circumference, the translucent blue of its lagoon is the stuff of a diver's dreams, with stunning visibility and scarcely a ripple to mar the surface on good days. Yet it hasn't always been as tranquil as this. The few passes that extend through the reef help produce that mirror-smooth calmness, but they also make the atoll an easily defendable natural harbour in time of war.

In 1914, Japan took advantage of German preoccupation with events in Europe and seized control of all German Pacific colonies north of the equator. Chuuk, or Truk as it is often called in English, was one of those so claimed, and Japan immediately set about building a advance base there for its navy. By the time World War II came around, Chuuk was reckoned to one of the strongest naval bases in the Pacific, fortified with numerous anti-aircraft gun emplacements, coastal defence batteries and minefields. When the tide in the Pacific War then turned in the US's favour later in the war, it was clear that Chuuk would have to be neutralised somehow.

With the atoll's passes guarded by guns and mines, and its main bases therefore beyond the reach of any US naval gun, any surface assault was likely to be bloody and by no means guaranteed to succeed. So Operation Hailstone, as it became known, was to mark a radical new direction in the American approach. The mass amphibious landings used prior to this had cost thousands of lives. Instead Chuuk was to be pulverised by a massive aerial assault by day and night.

The first reconnaissance flight took place on February 4 and revealed the presence of a number of Japanese Navy and merchant ships. This was the Japanese Combined Fleet,

under the command of Admiral Koga. Alerted to the possibility of attack by the overflight, Koga immediately ordered the warships to steam for Palau, but the merchant ships, carrying badly needed supplies for the garrison on Chuuk, remained to unload first.

On February 16-17, 1944, US aircraft from Task Force 58 flew over 30 sorties. With the skies emptied of enemy fighters, the bombing runs were cruelly efficient, especially after dark. By the end of the two days, 40 ships were resting on the bottom. Chuuk's usefulness as the Japanese Navy's advance base was effectively ended.

There were still a large number of fortifications and a sizeable garrison on Chuuk though, and so on April 29 the bombers returned to the island to complete the job started two months earlier. Again the enemy fighters were dealt with first before the bombers went into action. Another 20 or so ships were sent to the bottom and over 400 buildings

demolished. Though the island was not surrendered until the war was over, it's remaining facilities were too puny to be any further threat and the US forces moved on.

Peace breaks out

In the years after the war, Chuuk was first administered by the US Navy, then became part of the Trust Territory of the Pacific Islands. In 1986 it joined the islands of Kosrae, Pohnpei and Yap to form the Federated States of Micronesia, becoming officially known as Chuuk State.

Chuuk State comprises the main atoll itself, as well as three separate island groups outside the lagoon. Weno, the 13sqkm island capital, is home to the international airport, the main seaport, and most of the government offices, private sector businesses, hotels and dive operators. Other population centres are scattered around the state, making up a total population of around 65,000.

For the moment you first drop into the waters of Chuuk lagoon, you become aware of one of the outstanding features of Chuuk: its almost unnaturally clear water. With little current in the lagoon and no major land mass to produce any runoff of silt, the visibility can extend to 40m or more. The only drawback with this is that it can make you think you are not as deep as you are. Take a quick glance upwards to check your position in relation to the diveboat at 50m and you may be fooled into thinking you are at 30m. On a wreck that slopes away, or on a particularly big ship, this can lead you into going dangerously deep. Remember to keep an eye on your depth gauge.

Once you've got your bearings, it is time to make the most of the legacy of those wartime days 60 years ago: a lagoon floor littered with hulks at varying depths. In all, Operation Hailstone and its subsequent raids resulted in the sinking of over 60 Japanese ships, turning Chuuk into what is now recognized as the number one wreck diving destination in the world.

Not all of those wrecks are accessible to recreational divers, but equally diving the lagoon is not just for the more advanced or technical diver, indeed even snorkellers will find much to enjoy where coral-hung masts and superstructure extend up from the floor to within metres of the surface.

At least 19 ships can be completely explored with the diver never dropping below 33m, along with assorted plane wrecks and other wartime debris. Note that the wrecks are designated as an historic monument though - the removal of any artifacts is strictly prohibited. Note also that some of these wrecks are so large that it takes more than one dive to explore thoroughly and to appreciate the marine life in and around them.

Fin down to one of these ships and you are first hit with their immensity, readily apparent in these clear waters. Control your final descent so that you can enjoy this sensation of size for a moment, before you settle lower. Finally you reach the wreck, disturbing the silt that lies over them all thanks to the atoll's volcanic heritage. To then enter one of these ships is to exchange the large scale for a more human level. Alongside the war memorabilia are personal artifacts that quickly give you a sense of the men involved in those dark days. The chopsticks and beer bottles, shoes and other effects strewn across many of the wrecks are a sobering counterpoint to the fighter planes, trucks, shells, mines and general supplies that were the cargo of many of these ships at the time they were sunk.

The wrecks

One of the best known wrecks in the lagoon is the Fujikawa Maru, a 133m-long, passenger/cargo ship converted for use as an aircraft ferry. The Fujikawa sits perfectly upright on the sandy bottom, the deck at 18m and the bottom of her deepest hold twice that distance down. Shallow enough for a long dive, the ship is covered with lush corals that rival any reef in Micronesia. With 1-1.5m-wide anemones, schooling jacks all around, and invertebrates of all types, this wreck also makes a good night dive. There is a cargo of fighter planes on board and more than one diver has wiggled into the cockpit of a Japanese zero at 30m on this wreck. There's also a large variety of aircraft parts as well as other war materials from mess kits to machine guns scattered about. Cruise the deck, holds, rooms and hallways and you'll observe bottles, china teacups and countless other accoutrements of everyday life, alongside the military hardware. The engine room, bridge and officers' wardrooms with their tiled Japanese baths are all easily accessed too and contain numerous other personal artifacts.

Another must-dive wreck is the Yamagiri Maru, a 134m passenger/cargo vessel resting on its port side with easy access to its holds, rooms and cargo. The Yamagiri sank after being hit a number of times and in one area of this vessel, a human skull is fused to a portion of the hull. The skull of the unfortunate sailor was embedded in a nook in a starboard-facing bulkhead in the engine room by the force of the torpedo blast that holed the ship there. Unlike the starboard torpedo hole into the foreward holds (which faces up towards the surface), this torpedo hole is not readily visible because the ship lies on it. The front of the skull is blackened from an intense but short-lived fire that burned until the ship filled with water and sank. A piece of sheet metal blasted from somewhere in the room that is embedded just below the skull has caught some teeth, small bones, and bits and pieces of his uniform including the soles of his shoes. Elsewhere on the wreck, check out also the huge shells for 18in (59cm) calibre guns, each 1m long and weighing almost 700kg. Intended for the guns of the Japanese Navy's biggest battleships, they are now one of the signature sights on this wreck.

Also popular with divers is the large tanker, the Shinkoku Maru which makes an excellent night dive. It has the mother of all engine rooms, large bow and stern guns that are still intact, and a fascinating midships section with a galley and a clinic complete with operating table. Almost all the surfaces of the ship are overgrown with a covering of hard corals, anemones, hydroids, sponges and soft corals - enough to make Fiji weep with envy. The combination of the ship's accessibility (12-40m), its location in the current which brings in sharks and other pelagic life, and this prolific coral growth, make it one of those wrecks that demand at least a second dive.

The Hoyo Maru is an interesting accessible wreck just north of the island of Fefan. The shallow end of the ship is reachable by snorkellers and at first glance the hull can look like a natural feature as it is upside down. The wreck slopes away all the way down to 35m though and with it balanced on its superstructure, confident divers can swim right under, from one side to the other.

Kansho Maru is another medium depth wreck which is a must to dive. Rich in marine life with large soft and hard corals, it has an easily accessed interior with the skylights to the engine room open (though you'll need a light for sure) and interesting artifacts in the holds and galley.

Other easily reached wrecks include the Heian Maru and Kiyozumi Maru, between Fefan and Tonoas; the Hanakawa Maru near Tol; the Fumizuki Maru (discovered in 1987 off Udot) and the Sankisan Maru off Uman. All these ships are full of war and personal items with an abundance of marine life swimming in and out of open hatches, doorways, and torpedo holes.

The most famous deep wreck is the submarine tender San Francisco Maru, the only wreck in the lagoon resting on its starboard side, down at 40-60m. Deep is a relative term though. Many divers who do this wreck have not previously gone so far down, but with bathtub warm water, no thermoclines and no currents to speak of, deep wrecks don't get any easier than this. Experienced divers may find they don't even need a wetsuit and the only way to surface far from the boat would be to spend your whole dive swimming away from the wreck. Famous for the three battle tanks on her deck and photogenic bow gun, she also has trucks, beach mines and other war materials in her holds. Check out the fourth hold with its two trucks that have been much photographed.

Also deep is the Nippo Maru. On the main deck are three captured American howitzers, a truck chassis, gun barrels, a machine gun and a tank. In the holds are still more war materials and the bridge is another popular stop, with its ship's wheel, double-handed telegraph and compass.

The shallower wreck of the Hoki Maru is also popular with photographers, again partly because of its cargo of vehicles. Note that some of these are getting fragile after all these years so take care to not damage them.

Beyond these are the Aikoku Maru, the Amagisan Maru, the Fujisan Maru, and the Shotan Maru to name just a few. All of the wrecks have varying degrees of hard and soft coral growth, and a mix of military hardware and personal effects.

Once you have had your fill of the Japanese fleet, it is also worth remembering that they are not the only story here. With the visibility in the lagoon, it would be a shame to spend all your time in the confines of wrecks so broaden your horizons and check out the natural wonders too.

Shark Island for example, is a very small but picture postcard perfect island that offers great shark action. There is a cleaning station here surrounded by brilliant coral outcrops where you can observe black-tip and grey reef sharks at very close quarters, cruising by in crystal-clear waters at only 18m and with no current at all. This makes it an easy dive for all divers and the white sandy bottom makes it an ideal area for underwater photographers. Even with all the wrecks around, this dive counts as an absolute must during your stay, and is the perfect way to finish the day after the morning of scouting round the ships.

For something completely different, how about a trip to Chuuk's largely unexplored outer reefs? Easily arranged, the trips provide some excellent diving and are an opportunity to feel the thrill of being among a select few to have dived this often-neglected part of Chuuk.

Above the waves

Exploration needn't always mean donning tanks and regulator though. The small picturesque islands within the lagoon make for a relaxing spot for a break between dives, lazing under a coconut palm or perhaps venturing out to snorkel or free dive on the shallower wrecks.

Then there are the larger islands of Chuuk that retain their unsophisticated charm and a living culture that welcome the visitor more like a guest than a tourist. Despite all the treasures out in the lagoon, it's worth reserving a little time to see what they have to offer. The successive colonial heritages have created an unusual mish-mash of cultures and architectures, but unlying it all is the natural warmth of the Chuukese, and any chance to meet residents and brush up against their customs should be quickly accepted.

An interesting stop on any land tour is the Xavier High School which used to be the Japanese command centre during the war. Today it is Micronesia's most exclusive high school, with its list of graduates reading like a "Who's Who" of prominent political and business leaders of Micronesia.

The well preserved lighthouse is another sight to include, along with a number of caves still containing guns from the war on Weno Island. Other lagoon islands have left-overs from the war too: the old naval base - Little Tokyo as it is called - now houses a school, and there's also a church designed by the Germans and finished later during the Japanese occupation. It's an unusual take on colonial architecture which serves to underline just how important this sleepy Pacific backwater was felt to be during the tumultuous first half of the 20th Century. ÆÆ

Practicalities

Time: GMT + 10 hours

Country Code: 691

Electricity: 110/120V

Currency: US$. Major businesses accept Visa & MasterCard

Official languages: Chuukese and English

Weather: Averages 28ûC year-round, with the dry season running January-March and more rain coming in August-December. Of more concern perhaps are the occasionally strong gusting winds at some exposed sites - check conditions before you venture out. Water temperature is typically 27ûC so you'll only need a thin wetsuit at most.

Visas: Not required for visits up to 30 days and can usually be extended for an additional 30 days on request. Note that transfers in Guam may require a transit visa for some nationalities.

Getting there: Continental Airlines is currently the only airline serving Chuuk, running 1hr flights from Guam.

Accommodation & operators The Truk Stop Hotel & Dive Center is a PADI Resort offering all types of diving from beginner-level up to trimix technical diving. With the wrecks within easy reach, you can get in up to four dives a day. Their Hard Wreck Caf? & Bar is a popular apr?s dive spot. Tel: (691) 330 4232, website: www.trukstop.com

Alternatively you can choose to use a liveaboard instead:

Truk Aggressor II, tel: (1-800) 348 2628, website: www.aggressor.com

Odyssey, tel: (1-800) 757 5396, website: www.trukodyssey.com

SS Thorfinn, tel: (691) 330 3040, website: www.thorfinn.net