© 1998-2006 Bob Hackett and Sander Kingsepp

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14 December 1936:
Kure Navy Yard. Laid down as a seaplane carrier/tender and named CHIYODA.

19 November 1937:
Kure. Launched.

20 November 1937:
Captain (later Rear Admiral) Mizui Seiji is posted as the Chief Equipping Officer.

10 September 1938:
Captain Mizui is posted as CO.

15 December 1938:
Kure. Completed and commissioned in the IJN. Captain (Rear Admiral, posthumously) Kaku Tomeo [42] assumes command. Captain Mizui is posted as CO of sister ship CHITOSE. CHIYODA is assigned directly to the Combined Fleet. CHIYODA is equipped with four catapults and carries a complement of Type 94 Kawanishi E7K2 “Alf” and Type 95 Nakajima E8N2 Dave floatplanes. Her aircraft are coded "5-xx"

1939:
Departs for China. CHIYODA is later paired with tender KAMOI.

15 December 1939:
Captain (later Rear Admiral) Yokoi Tadao (former Attache to Germany) assumes command. Captain Kaku later assumes command of HIRYU and is KIA aboard her at Midway.

1 April 1940:
CHIYODA is assigned to the Special Duty Unit, 2nd China Fleet.

May 1940:
CHIYODA ends her tour in the China Theatre.

10 May 1940:
CHIYODA is redesignated as a special service vessel.

23 May 1940:
Kure Navy Yard. Drydocked. CHIYODA begins her first rebuild. She is modified to carry 12 midget submarines stored in pairs in the aircraft hangar. Her seaplane capacity is reduced from 24 to 12 aircraft.

23 June 1940:
The first rebuild is completed.

20 August 1940:
Captain (later Vice Admiral) Harada Kaku (former CO of HOSHO) assumes command.

September 1940:
Transferred to Vice Admiral Katagiri Eikichi's (former CO of HARUNA) Fourth Fleet at Truk.

11 October 1940: Imperial Naval Review:
Yokohama Bay. An Imperial Naval Review is held to celebrate the 2,600th anniversary of Emperor Jimmu’s enthronement. 98 IJN warships are present. That day many new IJN warships are shown publicly for the first time, including CHIYODA and seaplane carriers CHITOSE and MIZUHO and cruisers TONE and CHIKUMA.

November 1940:
CHIYODA is reassigned directly to the Combined Fleet.

15 November 1940:
A group of 13 officers and petty officers arrives aboard CHIYODA for classroom training in Type A improved ASW target (Ko-Hyoteki) midget submarines directed by Cdr (Rear Admiral, posthumously) Kato Ryonosuke.

January -March 1941:
The first group undergoes sea training and further instruction.

March 1941:
Departs Hashirajima for Takao, Formosa and returns to Hashirajima.

April 1941:
Training of the first group is completed. A second group of ten officers and 12 petty officers and ratings arrives and begins training. Sea training is conducted aboard CHIYODA and Captain (later Rear Admiral) Komazawa Katsumi's (former CO of CHOGEI) newly commissioned seaplane/submarine tender NISSHIN. Only two officers of all the midget submariners are volunteers; the rest are routinely assigned the duty.

May 1941:
Mitsukue Bay (Ehime Prefecture), off Shikoku. The second group of trainees simulates attacks on anchored vessels. Tug KURE MARU serves as temporary base.

June-July 1941:
Kure. CHIYODA undergoes a modification to her stern to form a ramp to enable her to launch midget submarines.

18 August 1941:
The second group conducts its final exercise, using CHIYODA as the target. During a subsequent conference, some crewmembers suggest use of the new weapon to penetrate enemy naval bases to attack capital ships. They also suggest the use of "mother" submarines as midget carriers to overcome the midget submarines' short range problem. Soon thereafter, training of the second group is completed.

Early September 1941:
Naval General Staff (NGS) liaison officer Cdr (Rear Admiral, posthumously) Ariizumi Tatsunosuke inspects CHIYODA. Captain Harada informs him of the harbor-penetrating concept and asks that Ariizumi forward the idea to the NGS. Harada, Lt Iwasa Naoji and Lt ( j.g.) Matsuo Keiu compile several studies about attacks on naval bases at Pearl Harbor, San Francisco, Hong-Kong, Singapore and Sydney.

Late September 1941:
Aki Nada, Inland Sea. To verify the feasibility of penetrating an enemy harbor with midget submarines, Captain Harada conducts a series of night exercises off Shikoku. The midget submariners practice attacking a defended harbor that, unknown to them, resembles Pearl Harbor and returning to the unlit CHIYODA at night.

8 December 1941: Commencement of Hostilities with the United States and Great Britain:
CHIYODA is at Kure.

31 January -2 March 1942:
Hiroshima Bay. Engages in training of embarked midget submarines.

20 March 1942:
Hashirajima. CHIYODA is assigned to Vice Admiral, the Marquis, Komatsu Teruhisa’s (former CO of CA NACHI) Sixth Fleet (Submarines) Advance Force with SubRon 8, NISSHIN and armed merchant cruiser AIKOKU MARU. CHIYODA's aircraft are coded "Z-xx"

15 April 1942:
Departs Hashirajima.

24 April 1942:
Arrives at Truk.

20 May 1942:
Departs Truk.

24 May 1942:
Arrives at Kure.

27 May 1942: Operation “MI” -The Battle of Midway:
In the afternoon, Vice Admiral Nagumo's First Air Fleet Striking Force's ("Kido Butai") CarDiv 1 AKAGI and KAGA and CarDiv 2 HIRYU and SORYU depart Hashirajima.

29 May 1942:
The First Fleet's Main Body consisting of BatDiv 1's YAMATO, NAGATO and MUTSU departs Hashirajima with Supply Group No. 1's oilers NARUTO and TOEI MARU and DesRon 3's light cruiser SENDAI with nine destroyers. CHIYODA and NISSHIN and light carrier HOSHO are assigned to the Main Body's Special Force as a reserve under the command of Captain (Vice Admiral, posthumously) Harada Kaku. The Main Body remains 300 miles behind Nagumo's Striking Force.

CHIYODA carries eight Type A midget submarines (HA-28, HA-29, HA-31, HA-32, HA-33, HA-34 and two others) and 16 crewmen. The Midway Invasion plan calls for the midget submarines to be stationed at Kure Island about 56 miles WNW of Midway. NISSHIN carries torpedo boats No. 4 and No. 5. The plan calls for the midget submarines to be landed the afternoon of 6 June 1942. Kure Island is then to also operate as a seaplane base for use against Midway. Additional midget submarines are to be landed on the island later that month.

4 June 1942:
At 0430, Nagumo launches a strike against Midway. At 1025, as carriers AKAGI, KAGA and SORYU are preparing to launch strike against American carriers, they are attacked by "Dauntless" SBD dive-bombers from USS ENTERPRISE (CV-6) and YORKTOWN (CV-5) and all are set afire. At about 1035, HIRYU is attacked unsuccessfully by Douglas TBD"Devastator" torpedo bombers of VT-3 from YORKTOWN. At 1054 and 1245, HIRYU launches strikes that heavily damage YORKTOWN. At 1703, while preparing to launch yet another strike, HIRYU suffers hits by four SBD's from ENTERPRISE and YORKTOWN and is set afire. At 1916, SORYU sinks by the stern followed at 1925 by KAGA that also sinks stern first.

5 June 1942:
At 0255, the C-in-C, Combined Fleet, Admiral (Fleet Admiral, posthumously) Yamamoto Isoroku (former CO of AKAGI) sends a signal from flagship YAMATO that cancels the invasion of Midway. Captain Harada receives the signal and orders CHIYODA, NISSHIN and HOSHO to set course westward.

14 June 1942:
CHIYODA and her embarked midget submarines return to Hashirajima with the Main Body.

15 June 1942:
At Kure. Refit.

20 June 1942 While at Kure, assigned to Northern Force Transportation Force.

25 June 1942:
The refit is completed. Departs Kure.

26 June 1942:
Arrives at Yokosuka. Assigned to the Northern Force’s Transportation Force.

28 June 1942:
CHIYODA departs Yokosuka for Kiska with troop transport ARGENTINA MARU (future KAIYO), DesDiv 18's ARARE, KASUMI and SHIRANUHI. CHIYODA carries Type A midget submarines HA-28, HA-29, HA-31, HA-32, HA-33 and HA-34, six Type 2 Nakajima A6M2-N "Rufe"single-seat float fighters, a 150-strong crew of the future midget submarine base, a detachment of the 12th Construction Batallion and 200-tons of cement.

5 July 1942:
CHIYODA arrives at Kiska. The midget submarines are assigned to the 5th Guard Unit, Special Purpose Unit. The 12th Construction Batallion detachment begins erecting a maintenance shed and four sets of launch rails in the west part of Kiska Harbor.

LtCdr (MOH, posthumously) Howard W. Gilmore's USS GROWLER (SS-215) attacks DesDiv 18's ARARE, KASUMI and SHIRANUHI anchored outside of the harbor. Gilmore sinks ARARE and damages SHIRANUHI and KASUMI.

That same day, CHIYODA is bombed by USAAF 11th Air Force planes, but suffers no damage.

12 July 1942:
Departs Kiska.

14 July 1942:
The code for CHIYODA’s floatplanes is changed to “V1-xx”.

19 July 1942:
Arrives at Hashirajima.

20 July 1942:
Arrives at Kure. Continues exercises with midget crews in the Inland Sea.

August 1942:
Remains in the vicinity of Kure.

25 September 1942: Operation "Divine Dragon No. 3" - Midget Submarine Attacks at Guadalcanal:
Departs Kure for Truk unescorted. She carries six Type A midget submarines.

30 September 1942:
Off Piaanu Pass, Truk. At 0520 (K), LtCdr (later Rear Admiral-Ret) Marvin G. Kennedy’s USS WAHOO (SS-238) sights CHIYODA at 12,000 yards, bearing 322 degrees true, on course 170 degrees true and zigzagging, but Kennedy cannot close the range to attack. At 0900 (local), CHIYODA arrives safely at Truk.

6 October 1942:
CHIYODA is tactically assigned to the Outer Seas Force, Reinforcement Force. During the month, she makes several trips to Shortland Islands anchorage, off Bougainville and nearby areas.

14 October 1942:
Arrives at Shortland with ComDesRon 3, Rear Admiral (later Vice Admiral) Hashimoto Shintaro (former CO of HYUGA) embarked and delivers eight midget submarines. The Combined Fleet staff suggests that the midget submarines be deployed to protect convoys in the area between Russell Island and Guadalcanal, but the idea is overruled by the CoS, Combined Fleet, Rear Admiral (later Vice Admiral) Ugaki Matome (former CO of HYUGA).

That same day, fleet submarines I-172 and I-26 are ordered to proceed to an area S of San Cristobal to recharge the batteries of Type A midget submarines delivered by CHIYODA.

18 October 1942:
Shortland. CHIYODA is bombed, but suffers no damage.

29 October 1942:
Shortland. CHIYODA is bombed, but suffers no damage.

31 October 1942:
Shortland. CHIYODA is again bombed, but suffers no damage. That same day, she is reassigned to the Advance Expeditionary Force.

1 November 1942:
Captain Harada is promoted Rear Admiral.

2 November 1942:
Shortland. The decks of Captain Ota Nobunosuke’s Attack Group’s I-20, I-16 and I-24 are each loaded with a midget submarine brought by CHIYODA. I-20, I-16 and I-24 are ordered to Indispensable Strait off Guadalcanal.

3 November 1942:
Departs Shortland for Truk with sister CHITOSE and destroyers AKATSUKI and IKAZUCHI.

6 November 1942:
Off Truk. At 0650, LtCdr John E. Lee's USS GRAYLING (SS-209) attacks incoming CHIYODA with three torpedoes, but fails to score a hit. GRAYLING is spotted by a E8N2 "Dave" floatplane on anti-submarine patrol from Truk. The Dave drops three 60-kg depth charges on GRAYLING that cause moderate damage.

CHIYODA arrives safely at Truk.

November 1942:
CHIYODA is assigned to the "C" Submarine Force of the Advance Expeditionary Force.

6 January 1943:
Departs Kure.

8 January 1943:
Arrives at Yokosuka. Designated a reserve ship.

9 January 1943:
Captain (later Rear Admiral) Beppu Akitomo (former CO of SORYU) assumes command. Rear Admiral Harada is posted CO of SubRon 7.

16 January to 21 December 1943:
Yokosuka Navy Yard. CHIYODA undergoes conversion to a conventional light aircraft carrier.

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Authors’ Notes:
Sources vary concerning the configuration of CHITOSE, CHIYODA, NISSHIN and MIZUHO. All were constructed as seaplane carriers capable of carrying 24 floatplanes. CHIYODA was later converted to enable her to carry 12 midget submarines. This modification reduced her floatplane capacity to 12 aircraft. NISSHIN, completed during wartime, was constructed as a seaplane/midget submarine carrier. While it has been suggested that CHITOSE and MIZUHO also carried midget submarines, Japanese sources do not support that assertion.

Thanks go to Tony Tully for his input to this TROM. Thanks also go to Dr. Higuchi Tatsuhiro of Japan.

- Bob Hackett and Sander Kingsepp.

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