Operation "MO”

On May 2, while the South Seas Detachment was boarding its transports, a force left Rabaul harbour for the small island of Tagula in the southern Solomons to establish a seaplane base in support of Operation "MO”. It landed without opposition the following day, and a few days later put a construction unit ashore on the large island of Guadalcanal to build an airfield.

The Port Moresby invasion force steamed south from Rabaul on May 4 in | five transports, well escorted. Off Bou - '

Gainville the convoy was joined by the light carrier Shoho, with six cruisers. Two fleet carriers, Shokaku and Zuikaku, stood by south of the Solomons. As the invasion convoy was nearing the eastern point of New Guinea on May 7. the carrier Shoho, in the lead, was attacked by U. S. carrier planes and sunk, along with a cruiser. Admiral Inouye then ordered the transports back to Rabaul.

The following day the Battle of the Coral Sea was fought between the U. S. carriers Lexington and Yorktown and the Japanese Shokaku and Zuikaku-the first carrier battle in history. One Japanese carrier was damaged, the other lost most of her planes. The Lexington was sunk. The battle was therefore not a clear-cut victory for either side; but the invasion of Port Moresby had been blocked. For this, credit was due to the U. S. Navy cryptanalysts in Hawaii who had cracked the Japanese fleet code and thus enabled the Allies to intercept the convoy.

Operation "MO” was not abandoned, only postponed; and the release of Japanese forces from the Philippines after the surrender of Bataan and Corregi-dor on May 6 made an expanded operation possible, with the Yazawa and Aoba Detachments at Davao and the Kawaguchi Detachment at Palau added to the South Seas Detachment, all to come under the 17th Army (Lieutenant-General Haruki-chi Hyakutake), which was established on May 18.

In Tokyo, euphoria was at its height. At Army headquarters in late May, Seizo Okada, a war correspondent assigned to the South Seas Detachment, had to fight his way through a crowd of "provincials” (Japanese Army slang for

V Pushing the jungle road across a gulch over a log bridge.

A This detail from a Japanese painting vividly expresses the desperate fight put up by the Japanese in their do-or-die attempt to take Port Moresby.

Civilians) clamouring for permission to go abroad with the Army. After receiving his credentials from a major, Okada asked for a pair of army boots. "Behind a screen that stood by the Major some staff officers were talking and puffing at cigarettes. One of them, as plump as a pig, broke in, 'Hey, what are you talking about? Boots? Don’t worry about your boots. You’ll get lots of beautiful ones out there-damned beautiful enemy boots’.

"The mocking words drove the other officers into a fit of boisterous laughter. They too, like myself or any other Japanese, were puffed up like toy balloons by the 'brilliant initial success’ of the Pacific War.”

A week later came news of the first crushing setback. At Midway on June 7 the Japanese Navy was decisively defeated by the U. S. fleet, with a heavy loss of carriers.

Plans for operations in the southern Pacific had to be revised. Assaults against New Caledonia, Fiji, and Samoa were postponed indefinitely; and, for lack of carriers. Operation "MO” was changed from an amphibious assault to a land attack on Port Moresby over the-Owen Stanley mountains, to be made by the South Seas Detachment with the help of the 15th Independent Engineer Regiment (Colonel Yosuke Yokoyama).

An advance echelon under Colonel Yokoyama, consisting of the engineers, a battalion of Horii’s 144th Infantry Regiment, a company of marines of the Sasebo 5th S. N.L. F., and some artillery, anti-aircraft, and service units, in all about l,800men, was to land between Gona and Buna, an Australian government station about ten miles down the coast, advance inland to capture Kokoda, and prepare they way for Horii’s main force to cross the Owen Stanley Range. Reconnaissance Zeros had spotted a red ribbon of earth winding over the mountains and assumed it to be a road. The engineers were to put it into shape to take trucks, if possible, or at least pack horses.

While the Yokoyama Force was embarking in Rabaul harbour. General Hyakutake on July 18 prepared a plan to assist Horii with a flanking seaplane attack based on Samarai at the entrance to Milne Bay, the 20-mile long, 7-mile wide bay at the eastern end of New Guinea. The Navy was to seize Samarai on August 25 with the help of a battalion of the Kawaguchi Detachment. In this latest version of Operation "MO”, the Yazawa Detachment, consisting mainly of the 41st Infantry Regiment (Colonel Kiyomi Yazawa), was allocated to Horii.