Japanese Intelligence Operations in Scandinavia during World War II

Abstract

Japanese intelligence operations in Scandinavia became active after the collapse of Poland in September 1939. Both the Japanese and the Finns exchanged information on Soviet military cryptography and tried to decrypt the enemy's codes. As a result of the cooperation, the Finns succeeded in decrypting Soviet naval code at the beginning of the Continuation War. Onodera Makoto, Japanese military attaché in Sweden, collected a lot of valuable information on the Allied Powers in the neutral country, though the General Staff in Tokyo disregarded them as unreliable.

Keywords:

• Japanese Intelligence
• Cryptography
• Onodera Makoto

Notes

1. “Nichi‐bei kaisen fuka nari,” on 8 December 1985.

2. Onodera, Baruto‐kai. It was published also in German, Swedish, and Estonian: Onodera, An den Stranden der Ostsee; Onodera, Mina år vid Östersjön; Onodera, Kindral, Kes ei soovinud s[otilde]da.

3. Japan Forum contains an important article on Polish‐Japanese collaboration from 1900 to 1945 and that by John W. M. Chapman included material on collaboration with the Finns and Estonians based on a post‐war interrogation of Onodera during a short stay in Sugamo Prison. Chapman, “Japan and Poland's”.

4. Onodera, Baruto‐kai, 169–72.

5. Throughout this paper, unless otherwise stated, the term is applied to the General Staff of the Imperial Japanese Army (Sanbô honbu).

6. Lehtonen, “Radiotiedustelu,” 172.

7. Pale, Totuus Stella Polariksesta.

8. Manninen, “Stella polaris‐asiakirjoja,” Stella Polaris , 2002.

9. “Historic Cryptologic Collection,” Box 118, 1100, 1101, 1143, 1144.

10. Alvarez, “Axis Sigint Collaboration”.

11. Ookubo, Tairo angô kaidoku. Hiyama, Angô wo nusunda otoko tachi: 35–40. “Japanese Wartime Intelligence”.

12. MJK. Hayashi, Wareware ha.

13. Nishihara, Zen kiroku, 58–60. MJK.

14. Ibid.

15. Interview with Asai, Isamu. Tokorozawa, 20 November 1993.

16. Pale, Totuus Stella Polariksesta, 8–9.

17. Talvisodan historia 4 , 211.

18. Pale, Suomen radiotiedustelu, 56–7.

19. Jatkosodan historia 1 , 218–21; Jatkosodan historia 6, 443.

20. Pale, Suomen radiotiedustelu: 60–1.

21. Leskinen, Vaiettu Suomen silta, 161.

22. Pale, Suomen radiotiedustelu, 60–1. Interview with Hirose, Eiichi. Tokyo, 8 May 1987.

23. Hiyama, Angô wo nusunda otoko tachi, 192–9.

24. Hiyama, Angô wo nusunda otoko tachi: 189–210. Alvarez, “Axis Sigint Collaboration,” 9–11.

25. Tajima, Nachizumu, 128–215.

26. Berlin to Tokyo, telegram no. 864 on 20 September 1941, “Japanese Diplomatic Translations”. This material consists of one of the Japanese military attaché telegrams related to the Soviet cryptography decrypted by the Americans in WWII. Until April 1943, the Americans had not decrypted the military attaché code. See, “Japanese Army Attache Messages”. It would be rather strange if the above telegram dated September 1941 had been already decrypted prior to that date. My research in NAII in Autumn 2000, however, makes it clear that the telegram was decrypted as late as 6 February 1946. The US cryptanalysts decrypted the backlog of telegrams intercepted in 1941 in order to analyze the Soviet cryptography in the early stages of the Cold War.

27. Helsinki to Vice‐Chief of the General Staff, Tokyo, telegram No. 586 on 11 November 1941, “Japanese Diplomatic Translations”. Interview with Hirose, Tokyo, 8 May 1987, and with Pale, Erkki. Helsinki, 29 August 1988. Pale, Totuus Stella Polariksesta, 11. Pale, Suomen radiotiedustelu, 108. Hiyama, Angô wo nusunda, 204. Dispatch from Japanese Legation, Helsinki to Finnish Ministry for Foreign Affairs on 25 June 1941, Hirose Eiiti, Personal Files: Japanese Mission. “Neuvostoliiton sotilaallisten (ja poliittisten) salakirjoitusmenetelmien yleisseloisut” (“OPUS” Osa III), No. 6, Salasanomien Ratkaisutoimintaa Meriryhmässä (1.7.40)”: 14a, Box 7, Pale Papers.

28. Helsinki to Vice‐Chief of the General Staff, Tokyo, telegram No. 762 on 21 April 1942, “Japanese Diplomatic Translations”.

29. The following Finnish Army cryptographic documents are in the National Archives II: “Poriadok sostavleniia i raboty shifrom PULIA,” 5038N; “Prabila pol'zovaniia kodoy ZVEZDA,” 5039N, Box 1100, HCC. On analysis of these documents: “Mo:n avausjaoksen katsaus N:o1, Tammi‐ helmikuu 1942”; “Mo:n III jaoksen katsaus N:o 6, Kesä‐ ja heinakuu 1944,” 5051N, Box 1101, HCC.

30. Interview with Pale, Helsinki, 29 August 1988.

31. Pale, Suomen radiotiedustelu, 108–9. The Finnish collection in the National Archives II contains many German materials on the Soviet cryptography. For example, Chef HNW, Leitstelle d. Nachr. Aufkl. “Beheim Namensliste der Offiziere der NKWD‐Truppen, Stand: 25.10.1943,” 5020N, Box 1100, HCC.

32. “Tiesikö Mannerheim”.

33. Onodera, Baruto‐kai, 142, 147, 154–5.

34. Onodera, Baruto‐kai, 95. Pałasz‐Rutkowska, Romer, Historia stosunków Polsko‐Japońskich, 206–22. Rutkowska and Romer, “Dainiji taisen to himitsu chôhô katsudô”: 40–58. McKay, From Information to Intrigue.

35. “Japanese Espionage in the Reich.” It is the German documents translated into English relating to Onodera's activities in Stockholm collected by OSS. Chapman gave this report to the NHK during the production of the programme “Nichi‐bei kaisen fuka nari”.

36. Onodera, Baruto‐kai, 146–51.

37. Ibid., 99–100.

38. Interview with Onodera, Yuriko. Tokyo, 25 March 1992. Onodera, “Stella Polaris sakusen,” 73–9.

39. Ahtokari, Asekatkentajuttu, 172–3. Heiskanen, Stella Polaris, 24–8. Pale, Suomen radiotiedustelu: 30–5.

40. Interview with Pale, Helsinki, 29 August 1988.

41. Pale, Totuus Stella Polariksesta, 45, 52–3.

42. Onodera, Baruto‐kai, 171. Pale, Totuus Stella Polariksesta: 54, 89–94. See Note 8 for proof that the Finns took a microfilm and made photocopies.

43. Onodera, Baruto‐kai, 170–3.

44. http://www.nsa.gov/docs/venona/monographs/monograph‐6.html (Homepage of the US National Security Agency).

45. Interview with Hirose, Tokyo, 8 May 1987.

46. Interview with Pale, Helsinki, 29 August 1988.

47. The “Magic” background of Pearl Harbor , vol. 5, no. 5, 25–30.

48. Interview with Asai, Tokorozawa, 20 November 1993.

49. Interview with Onodera, Tokyo, 25 March 1992.

50. Johula, Paulaharju, Strömberg, Päämajan Hukatut kuukaudet, 106–8; 188–93.

51. Momose, Hokuô gendai shi, 285–6.

52. Interview with Pale, Helsinki, 29 August 1988.

53. Interview with Onodera, Tokyo, 25 March 1992. Onodera, “Stella Polaris sakusen,” 73–9.

54. “Japanese Wartime Intelligence”.