# Hiburi-class escort ship

The Hiburi-class escort ship (日振型海防艦,, Hiburi-gata Kaibōkan) was a design development from the Mikura-class escort ships of the Imperial Japanese Navy (IJN), serving during and after World War II.

## Background

In the Rapid Naval Armaments Supplement Programme of 1941, the Imperial Japanese Navy ordered the construction of thirty escort vessels (kaibōkan) – designated as #310 to #339 of that Programme, to provide escort ships for the Navy. Fourteen of these were planned as Etorofu class (Escort ship Type-A) of 860 tons standard displacement and sixteen as Mikura class (Escort ship Type-B) of 940 tons, although in the Budget (for which 153,360,000 yen was provided for the ships, or 5,112,000 per ship) they were all stated to be of 1,200 tons. However, three of the Mikura class (ships #328, #333 and #339) were subsequently designated as to be built to the Hiburi design.
In the next year's Modified 5th Naval Armaments Supplement Programme, the IJN ordered the construction of another thirty-four ships to a modified version (Ukuru class) of the Type-B design; these were designated as #5251 to #5284 of that Programme. However, eight of these ship (ships #5252, #5254, #5257, ##5259 and #5263 to #5266) were subsequently designated to be built to the Hiburi design. Only six of the eight were so completed, with #5265 and #5266 being incomplete at the end of the Pacific War and broken up.
The eleven ships were all ordered from the Hitachi Zōsen shipbuilding concern at Sakurajima, which had also received other orders for ships completed to the Etorofu, Mikura and Ukuru designs. The Hiburi design used the same hull as the Ukuru class, but with different fittings. In 1943, the Japanese Navy General Staff (Gunreibu) promoted the building of Escort ship Type-A, the Etorofu class and Escort ship Type-B, the Mikura class and Ukuru class. However, the Navy General Staff also noted that too many man-hours of work were needed for their building.

## Design

* The Navy Technical Department (Kampon) used the Ukuru's basic designs for the new drawings. It was a chimera of Mikura and Ukuru classes.
* The new drawings had the following characteristic.
** Armaments and under waterline designs were same as Mikura.
** Everything else was same as in the Ukuru.
* The Kampon estimated man-hours for building will be between 42,000 to 40,000.
* The new drawing was sent to the Hitachi Zōsen Corporation, Sakurajima Shipyard. Those ships of the Mikura class and the Ukuru class that had not been started were converted to the Hiburi class. The Hitachi Zōsen built all of the Hiburi class vessels.

## Ships in class

Of the nine ships completed, three were sunk by US submarines and two by naval mines.
| Ship # | Ship | Laid down | Launched | Completed | Fate |
| #328 | Hiburi (日振) | 3 January 1944 | 10 April 1944 | 27 June 1944 | Sunk by USS Harder at west of Manila, 22 August 1944. |
| #333 | Daitō (大東) | 17 April 1944 | 24 June 1944 | 7 August 1944 | Sunk by naval mine at Tsushima Strait, 16 November 1945. |
| #339 | Shōnan (昭南) | 23 February 1944 | 19 May 1944 | 13 July 1944 | Sunk by USS Hoe at south of Hainan Island, 25 February 1945. |
| #5252 | Kume (久米) | 26 May 1944 | 15 August 1944 | 25 September 1944 | Sunk by USS Spadefish at Yellow Sea 33°54′N 122°55′E﻿ / ﻿33.900°N 122.917°E﻿ / 33.900; 122.917, 28 January 1945. |
| #5254 | Ikuna (生名) | 30 June 1944 | 4 September 1944 | 15 October 1944 | Decommissioned on 30 November 1945. Transferred to Meteorological Agency 26 December 1947, and renamed Ikuna-maru. Transferred to Maritime Safety Agency 1 January 1949, and renamed Ojika (PS-102). Decommissioned on 25 May 1963. |
| #5257 | Shisaka (四阪) | 21 August 1944 | 31 October 1944 | 15 December 1944 | Decommissioned on 15 September 1945. Surrendered to Republic of China on 6 July 1947, and renamed Huian. Defected to People's Liberation Army 23 April 1949. Sunk by aircraft at Yanziji, 28 April 1949. Repairs were completed on 24 December 1953, and given the pennant number 218. Decommissioned in 1990. |
| #5259 | Sakito (崎戸) | 7 September 1944 | 29 November 1944 | 10 January 1945 | Decommissioned on 20 November 1945. Scrapped January 1947. |
| #5263 | Mokuto (目斗) | 5 November 1944 | 7 January 1945 | 19 February 1945 | Sunk by naval mine at Kanmon Straits, 4 April 1945. |
| #5264 | Habuto (波太) | 3 December 1944 | 28 February 1945 | 7 April 1945 | Decommissioned on 23 October 1945. Surrendered to United Kingdom on 16 July 1947, later scrapped. |
| #5265 | Ōtsu (大津) | 12 January 1945 | 10 May 1945 | | Not completed by the end of the war (95%). Scrapped on 25 March 1948. |
| #5266 | Tomoshiri (友知) | 5 March 1945 | | | Not completed by the end of the war (20%). Scrapped on 23 October 1947. |

## Appendix

* Classification of the Kaibōkan classes in IJN official documents
** The Shimushu, Etorofu, Mikura, Hiburi and Ukuru were classed in the Shimushu class.
** The IJN changed their classification on 5 June 1944, because the shipyards and commanders were confused.
** The Escort ship Type-B and Modified Type-B were combined to the Escort ship Type-A, and Type-Bs became extinct thereby.
| Before 5 June 1944 | Before 5 June 1944 | Before 5 June 1944 | >> | And after 5 June 1944 | And after 5 June 1944 | And after 5 June 1944 |
| Plan names | Official class names | Common class names | >> | Plan name | Official class names | Common class names |
| Type-A | Shimushu class | Shimushu class | >> | Type-A | Shimushu class | Shimushu class |
| Type-A | Shimushu class | Etorofu class | >> | Type-A | Shimushu class | Etorofu class |
| Type-B | Shimushu class | Mikura class | >> | Type-A | Mikura class | Mikura class |
| Type-B | Shimushu class | Hiburi class | >> | Type-A | Mikura class | Hiburi class |
| Modified Type-B | Shimushu class | Ukuru class | >> | Type-A | Ukuru class | Ukuru class |
| Type-C | No.1 class | No.1 class | >> | Type-C | No.1 class | No.1 class |
| Type-D | No.2 class | No.2 class | >> | Type-D | No.2 class | No.2 class |

## Gallery

(Changes of equipment and under waterline design)
* Daitō or Shonan in August 1944
* Ikuna in October 1944
* Shisaka in December 1944
* Habuto in April 1945
* Ōtsu in 1945
* Disarmed Shisaka (left) and Yukikaze in Tokyo, after they were used to repatriate Japanese nationals from overseas, May 1947
* Shisaka in May 1947