Chapter IV
Japanese Reaction

0652, August 7th to 2400, August 7th

(a) Operations of Japanese Cruiser Force

The Japanese cruisers Chohkai and CRUDIV SIX had sortied at 0615 from Silver Sound, where they had been basing since August 1st, and had cleared the southern entrance to Steffen Strait at 0650. At that time the Chohkai and Section One of CRUDIV SIX (Aoba and Kaka) had set the course for Sweadler Harbor, Manus Island, and Section Two (Kinugasa and Furutaka) had headed for Rabaul. At 0652 each of the five cruisers intercepted the urgent dispatch from Commander Air Base, Tulagi that reported: "Enemy task force sighted!"*

The reaction of the Japanese unit commanders concerned was spontaneous and correct. The Commanding Officer, Chohkai, immediately reversed course toward Rabaul. COMCRUDIV SIX, in the Aoba, cancelled the orders of Section One to proceed to Manus, and ordered the Aoba and Kako to proceed to Rabaul** at twenty-four knots, notifying Commander EIGHTH Fleet at Rabaul of his action.*** He reformed CRUDIV SIX in column and joined in behind the Chohkai.

Meanwhile Commander Outer South Seas Force, who was at Rabaul, was studying the situation. He had been expecting some form of Allied attack in the Solomons Area, but not at this time. The Japanese records available to this study do not divulge his mental processes at the time, but there can be no doubt as to his serious concern over the nature of the Allied effort at Tulagi.

In the meantime, the routine air searches scheduled for August 7th were commenced. At 0700, two Type-97 seaplanes departed Rabaul to search the sector between bearings 100°(T) and 130°(T) from Rabaul to a radius of 700 miles.****

At 0725, Commander Outer South Seas Force received the amplifying report from Tulagi that he had been anxiously awaiting. This urgent dispatch had been released by Commander Tulagai Air Base twenty minutes before, and reported: "Enemy task force of twenty ships attacking Tulagi;


*CRUDIV 6 Detailed battle Report #8, Solomon Naval action, August 7th-10th, 1942, CIG Document S6927 June 27th, 1947, pages 2 and 6.
**CRUDIV 6 Signal Order 289.
***COMCRUDIV 6 Classified Dispatch #246, August 7th, 1942.
**** Japanese Search Plans, August 7th to 9th, 1942, CIG Document 74632, May 12th, 1947, page 2.

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undergoing severe bombings; landing preparations underway; help requested."*

This dispatch provided Commander Outer South Seas Force with an accurate estimate of ships attacking Tulagi, since in fact there were twenty-two ships of all classes at Tulagi.** He knew, of course, from this dispatch that there must be a supporting force of Allied carriers somewhere in the vicinity of Tulagi to have carried out the bombing attacks reported. No reports were received from Guadalcanal and it is possible that Commander Outer South Seas Force based his initial estimate of the total strength of the Allied effort upon the report from Tulagi.

He shortly was handed a dispatch, sent at 0725 by Commander YOKOHAMA Air Group at Tulagi addressed to commander FIFTH Air Attack force, which reported: "All large flying boats burned as a result of the 0630 air attack."

The situation confronting Commander Outer South Seas Force was somewhat as follows: the Allied attack on Tulagi was a complete surprise since the Japanese had made no contact whatsoever on the Allied force until it struck. It was in strength, and constituted a serious menace to the Japanese positions in the Solomon Islands. If these positions were to be held by the Japanese, the defending forces at Tulagi must be given immediate help. Continuous air attacks on the allied transports and cargo ships might destroy many of them, and would have a serious delaying effect on the unloading schedule of the remainder. Anchored transports were excellent targets for Japanese submarines. But air and submarine attacks were not enough in the face of Allied screening ships and carrier-based aircraft. He concluded that a bold offensive by surface ships also was needed, and decided "to put the fleet into action immediately to destroy the enemy."***

He therefore prepared his counterattack. He had been informed by dispatc of the initiative of the Commanding Officer, Chohkai and of COMCRUDIV SIX in proceeding to Rabaul. At 0749 he directed the Yunagi to make full speed and escort the Chohkai into Rabaul Harbor. He also directed the Tenryu, Yubari and the Yunagi to be prepared at 1300 to depart from Rabaul to attack the Allied ships in the Tulagi area.***

He continued to receive reports from Tulagi of fierce naval bombardment, air bombing attacks, and of the initial landings until 0805 when communications ceased.*** The last dispatch received at that time reported


*CRUDIV 6 Detailed Battle Report #8, Solomons Naval Action, August 7th-10th, 1942, CIG Document 86927, June 27th, 1947, pages 3 and 6.
**War diary CTF 62, July 18th to August 31st, 1942; and Annex I to CTF 62 Operation Plan A#-42.
***Commander 8th Fleet's Estimate of the Situation regarding American Landings on August 7th, 1942, on Guadalcanal and Tulagi, CIG Document 73845, May 7th, 1947.

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"The enemy was in great force; but that no matter what the odds, the garrison would fight bravely to the last man, praying for everlasting victory."*

The disruption of communications from Tulagi denied Commander Outer South Seas Force the further information he desired of the enemy. Accurate intelligence of the strength, disposition and activities of Allied forces was of primary importance in the promotion of his freedom of action. Seaplanes had already commenced search operations at 0700 in the Tulagi sector. Undoubtedly he knew, as the Allies had discovered at the Battle of Midway, that seaplanes are generally unsuitable for reconnaissance in an area where air opposition would be encountered. At any rate, additional searches were commenced at 0900, employing land attack planes rather than seaplanes.** Commander FIFTH Air Attack Force DESOPORD No. 195, ordering his search, was timed at 0910,** ten minutes later than the actual time of takeoff of the search planes.** The indications are that preliminary orders were given by Commander FIFTH Air Attack Force either by telephone or in conference, to his subordinate commander, Commander SECOND Air Group (who conducted the search) and were followed up with confirmation by dispatch orders. The urgency of the searches by land attack planes on August 7th is accented by the fact that the directives for searches on subsequent days were each given on the day preceding.

The land-attack planes from the SECOND Air Group conducted reconnaissance missions to a radius of 700 miles from Rabaul over courses and lateral distances as follows:

Plane Course Out Lateral Distance
No. 1 170°(T) 60 miles to the left
No. 2 117°(T) 60 miles to the left
No. 3 127°(T) 60 miles to the right

A study of these searches, as depicted on diagram "C", indicates that searches by plane number two and three were well designed to cover the area in the vicinity of the Tulagi landing. The search of plane number one covered in an isolated sector interposed between Tulagi and the Australian mainland from where, as a far as Commander Outer South Seas Force knew, the Allied forces may have been mounted.

The offensive of Commander Outer South Seas Force included the immediate launching of air attacks on the Allied naval forces at Tulagi. At 0900, simultaneous to the departure of the search planes, commander FIFTH Air Attack Force sent off an air attack group composed of twenty-seven


*Commander 8th Fleet's Estimate of the Situation regarding American Landings on August 7th, 1942 on Guadalcanal and Tulagi. CIG Document 73845, May 7th,1947.
**Japanese Search Plans, August 7th-9th, 1942, CIG Document 74632, May 12th, 1947.

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land attack planes of the FOURTH Air Group and eighteen Zero fighters of the TAIMAN Air Group.* At about 1045 a second air attack group, composed of sixteen Type-99 land-based carrier bombers of the SECOND Air Group, was launched to attack the Allied forces at Tulagi.** This latter attack group undoubtedly staged through the Japanese airfield at Buka Passage, since the range capability of the carrier bombers would otherwise have been inadequate for this operation.***

Commander Outer South Seas force "decided, depending on the results of the reconnaissance and counterattacks of our air force to the south, to strike the anchored enemy convoys at night and destroy them."*

With this plan in mind, he organized a naval force (hereinafter referred to as the Japanese Cruiser Force) composed of the Chohkai as flagship, the four heavy cruisers of CRUDIV SIX, the light cruisers Tenryu and Yubari of CRUDIV EIGHTEEN and the only available destroyer, the Yunagi.

This plan depended upon the reports from his reconnaissance planes launched at 0700 and again at 0900. It also called for accurate information on the results of the two bombing attacks launched against the enemy, one at 0900 and the other at 1045. By 1110 the two search seaplanes had reached the 700 miles radius from Rabaul on tracks 107°(T) and 117°(T), then proceeded on their sixty miles lateral legs, and at 1131 headed back to Rabaul. Their reconnaissance had been restricted, as can be seen by referring to Diagram "C", to the area northeast of the southern Solomons. The weather southeast of Tulagi was reported to be bad, making reconnaissance impossible.**** The enemy was not sighted.****

Commander Outer South Seas force requested that a reconnaissance plane be sent to Tulagi to make direct observation of the results of the Japanese bombing attacks on the Allied ships there. At 1120, commander FIFTH Air Attack Force ordered one land attack plane from the SECOND Air Force to proceed from Rabaul at 1145 to carry out this reconnaissance mission at Tulagi and Guadalcanal.**** This plane actually took off at 1202.****

At 1203, the Chohkai and CRUDIV SIX enroute from the Kavieng Area to Rabaul, sighted the Yunagi approaching the formation from a position fifteen and one-half miles away on bearing 193°(T).***** The Yunagi


* Commander 8th Fleet's estimate of the Situation on August 7th, 1942, CIG Document 73845, May 7th, 1947.
** Strength and disposition of 25th Air Flotilla on August 7th, 1942, CIG Document 74629, May 12th, 1947.
*** "Japanese Aircraft Performance Characteristics", Technical Air Iintelligence Center (TAIC) Manual No.1, OpNav 16-VT #301.
**** Japanese Search Plans, August 7th-9th , 1942, CIG Document 74632, May 12th, 1947.
***** CRUDIV 6, CIG Document 86927, June 27, 1947.

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effected rendezvous with the Chohkai at 1224, and escorted her into Rabaul. CRUDIV SIX continued on to Rabaul separated from the Chohkai and Yunagi.*

At 1239, these Japanese cruisers had reached a position about twenty-five miles north of Rabaul and sighted thirteen Allied B-17's attacking Rabaul.* The cruisers prepared to repel air attacks, and maneuvered to the westward until 1243 when the B-17's disappeared. Although this cruiser force was sighted and reported by the B-17's, it was not attacked. So far as the Japanese cruiser commanders could surmise, the airfields at Rabaul were more profitable targets for the B-17's than were the cruisers.

The Japanese air units at Rabaul endeavored to repel the B-17 attack group, employing the twenty-one Zero fighters at Rabaul.** They succeeded in destroying one B-17,*** but suffered damage to seven fighters of the TAIMAN Air Group and to one fighter of the SECOND Air Group.**

By 1307 the three Japanese land attack planes on search missions arrived at the outer limit of their sectors. They proceeded along their respective cross-legs, and at 1328 turned back toward Rabaul (where they landed at 1735). The combined reconnaissance of both land and seaplane searches detected one Allied seaplane in Task Force 63 Sector IV and the Allied ships at anchor in the Tulagi-Guadalcanal area.*** Perhaps the Japanese search plane on leg 127°(T) from Rabaul was discouraged by bad weather (reported by the Japanese in the southern Solomons and reported by Allied search planes in Sector I and II) and had turned back before he reached the Allied Air Support Force (TG 61.1) which was operating in his search sector. The Allied carriers reported a heavy overcast sky, but conducted flight operations below this overcast in good visibility.*****

At 1325, the first Japanese air attack struck at the Allied ships at Guadalcanal. This attack group encountered the opposition of Allied carrier-based fighters and anti-aircraft fire from the Allied ships. It suffered the following casualties: three attack planes and two fighters shot down, two attack planes made emergency landings, and nineteen attack planes and two fighters were damaged.** The Japanese in turn succeeded in shooting down nine Allied fighters and in dropping all bombs. No hits were made on the Allied ships, however since the bombs fell well clear of the surface targets, landing between the transports and the cruisers.*****


*CRUDIV 6 Detailed Battle Report #8, Solomons Naval Action August 7th-10th, 1942, CIG Document 86927, June 27th, 1947.
**Strength and disposition of 25th air Flotilla on August 7th, 1942, CIG Document 74629, May12, 1947.
***Operation Report, Allied Air Forces, Southwest Pacific Area for August 7th, 1942.
****Japanese Search Plans, August 7th-9th, a942 CIG Document 74632, May 12th, 1947.
*****War Diary, Enterprise, August 1942.
******War Diary, American Legion, August 1942, Report of Action off Guadalcanal, August 7th, 1942.

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Compiled and formatted by Ellis Greenstein, for the HyperWar Foundation