Stories and Battle Histories of the IJN's Subchasers

12 November 2019

By Bob Hackett, Sander Kingsepp and Peter Cundall

Discussion & Questions

(Subchaser No. 46 by Takeshi Yuki)

The Japanese Navy was not preparing for a defensive war, so their first submarine chaser was not ordered until 1931. Eventually, 64 purpose-built subchasers were ordered, most during the prewar years. The IJN's subchasers carried 36 depth charges and most were fitted with depth charge throwers.

After the fall of the Netherlands East Indies in 1942, 30 Dutch patrol boats and small minesweepers, including some under construction, were captured. Most had been scuttled, but the Japanese had them refloated and converted to auxiliary subchasers. In their homeland, the IJN requisitioned over 200 small merchant ships and had them converted to auxiliary subchasers.

Woefully short of destroyers and frigates, the IJN employed a motley array of largely ineffective subchasers, minelayers, minesweepers, netlayers and other small craft to escort their vital convoys. In 1944, the IJN's subchasers were rearmed and re-equipped; their light machine-guns were replaced by triple-mount 25-mm type 96 AA guns and a radar set (either Type 13 or Type 22) was fitted.

This page covers the activities of 61 purpose-built IJN subchasers.

In some cases, data for these small combatants are incomplete and the authors could not find details of movements for some time frames. Readers with access to such data are requested to post the information on the Discussion and Questions board or at the IJN Ship Message Board.

Tabular Records of Movement (TROMs):


(Subchaser Classes link to specifications summaries)

CH-1 Class

CH-1 (revised 12/15/17)

CH-2 (revised 12/15/17)
CH-3 (revised 10/19/18)
CH-4 Class

CH-4 (revised 10/26/18)

CH-5 (revised 6/9/18)
CH-6 (revised 10/19/18)
CH-7 (revised 6/9/18)
CH-8 (revised 6/9/18)
CH-9 (revised 11/15/18)
CH-10 (revised 12/15/17)
CH-11 (revised 6/9/18)
CH-12 (revised 10/19/18)

CH-13 Class

CH-13 (revised 3/12/16)

CH-14 (revised 3/12/16)
CH-15 (revised 12/22/17)
CH-16 (revised 3/26/17)
CH-17 (revised 12/22/17)
CH-18 (revised 12/22/17)
CH-19 (revised 11/15/18)
CH-20 (revised 6/9/18)
CH-21 (revised 6/9/18)
CH-22 (revised 12/22/17)
CH-23 (revised 6/15/18)
CH-24 (revised 6/15/18)
CH-25 (revised 3/27/16)
CH-26 (revised 6/15/18)
CH-27 (revised 3/27/16)

CH-28 Class

CH-28 (revised 12/22/17)

CH-29 (revised 9/3/16)
CH-30 (revised 12/27/17)
CH-31 (revised 4/2/17)
CH-32 (revised 12/27/17)
CH-33 (revised 5/21/15)
CH-34 (revised 9/4/16)
CH-35 (revised 6/15/18)
CH-36 (revised 4/2/17)
CH-37 (revised 12/27/17)
CH-38 (revised 4/9/17)
CH-39 (revised 4/9/17)
CH-40 (revised 7/13/14)
CH-41 (revised 6/15/18)
CH-42 (revised 12/27/17)
CH-43 (revised 6/15/18)
CH-44 (revised 6/15/18)
CH-45 (revised 4/9/17)
CH-46 (revised 12/27/17)
CH-47 (posted 5/25/15)
CH-48 (revised 12/27/17)
CH-49 (revised 1/7/18)
CH-50 (revised 5/25/15)
CH-51 (revised 4/22/13)
CH-52 (revised 5/25/15)
CH-53 (revised 11/12/19)
CH-54 (revised 4/22/13)
CH-55 (revised 7/5/12)
CH-56 (revised 6/23/18)
CH-57 (revised 4/10/16)
CH-58 (revised 1/7/18)
CH-60 (revised 11/12/19)
CH-61 (revised 4/9/17)
CH-63 (revised 9/4/16)

Bibliography of Sources

About the Authors

Bob Hackett is a military historian and researcher. Retired from the United States Air Force and later from the aerospace industry, he resides in the United States.

Sander Kingsepp, a native of Estonia, is also a military historian and researcher. A talented linguist, Sander's translations of Japanese source materials have greatly enhanced these TROMs.

Peter Cundall is a maritime historian and researcher who specializes in merchant ships. He works in the maritime industry and resides in Australia.

Questions to the authors concerning these TROMs should be posted on the Discussion and Questions board.