by DAVID KAHN
1 teletype: 33:765, 8:3559.
1 page-printer: 8:3579.
1 carbon, yellow and pink: 8:3806, 9:4123.
1 apparatus: 3:1130, 9:4001.
2 key: 8:3778.
2 orientation: 8:3897.
2 sticker, hand-carried: 33:765, 844.
2 after 5 a.m.: my estimate. Decryptment on the PURPLE machine would take “a very few minutes … less than fifteen” (9:4001). Brotherhood does not remember whether an Army translator was on duty by 4 a.m., which suggests that, since he was thinking about translation, he had decrypted the message by then, but does remember that by 7 a.m., he had made one or two trips to the Army office (33:844). Thus, the intercept went to the Army some time between 4 and 7 a.m.
2 “Will the Ambassador”: 12:248.
2 14th part: 12:245.
2 Pering: 33:765.
2 Kramer arrives: 9:4006.
2 Bryant: 8:3611.
2 14 copies: 33:848.
3 Anderson names MAGIC: Wohlstetter, 75; Anderson, telephone interview, January 8, 1965.
3 McCollum, traffic and other deliveries: 9:4006, 4038, 4043-7.
3 Kramer sees one o’clock message: 8:3908.
3 unusual hour: 2:930.
3 time circle: 8:3910.
4 folders and briefcases: 29:2451, 34:95, 3:1324, 4:1927. 4 inserts dispatches, deliveries: 8:3908-9, 3393-4.
4 on the double: 9:4109.
4 “merits”: Report, 232.
5 Zacharias: his Secret Missions (New York: G. P. Putnam’s Sons, 1946), 83-84, 88-90, 97-108.
5 Rooms 2646 and 1649: Zacharias, 83; Claus Bogel, letter, May 8, 1925, in Manly Papers, University of Chicago Library.
5 to Corregidor: 26:387.
5 other units: 36:61.
5 Army: Yardley, 37, 240, 370, 250-317; The Origin and Development of the Army Security Agency, anonymous, undated, mimeographed document, but apparently based on official sources, at 2-4; Harris, 330-333.
6 1934: Lindsay Parrott, International News Service story of May 24, 1934; interview, Juichi Yoshida, September 12, 1962; Senate, Committee on Armed Services, Enhancing Further the Security of the United States, Report No. 1433, 80th Congress, 2nd Session, May 28, 1948 (GPO, 1948), 4.
6 Enigma: [United States, Department of the Army.] Headquarters, Army Forces Far East, Military History Section, Operational History of Naval Communications: December 1941-August 1945, Japanese Monograph No. 118 (Department of the Army: Office of the Chief of Military History, 1953), 67. Other information that came to my attention too late to include in my text is in Ladislas Farago, The Broken Seal (New York: Random House, 1967), 59-60, 74-75. Farago’s material must, however, be used with great caution, as it has many errors.
6 HATO: Ibid., 94; PHA, 35:463.
6 1936 to 1940: 9:4584, 34:10-11.
6 Mauborgne: 2:951, 3:1546, 34:83; his An Advanced Problem in Cryptography and its Solution (Fort Leavenworth, Kansas: Press of the Army Service Schools, 1914); Terrett, 13; Mauborgne, “One Method of Solution of the Schooling ‘Absolutely Undecipherable’ Cryptogram,” Articles, 227-240 (April-June, 1939); The Origin and Development of the Army Security Agency, 9-12; Army biography; “Secrecy for Sale” chapter and notes.
7 “If we have war …”: Lord, 12.
7 Rochefort: Navy biography; 10:4672-3, 8:3395, 3403-4, 26:217.
7 Combat Intelligence Unit: 32:358, 10:4673-4, 4697-8.
7 Japanese naval codes: 18:3335, 10:4673.
7 unit’s personnel: 10:4673.
8 net: 28:863, 23:675.
8 KUNA 1: 37:744.
8 reliance on radio intelligence: 36:14-15, 8:3383.
8 three stages: 28:870, 10:4834-5.
9 blank condition, low power: 10:4903-4, 23:659. 9 covering force, July, February: 10:4839, 4833.
9 S.I.S. size and organization: The Origin and Development of the Army Security Agency, 14; PHA, 3:1146.
9 Doud: 35:105; Army biography.
9 no Japanese military solutions: 35:106, 37:1061.
9 Rowlett, Svensson: 35:34.
9 OP-20-G: 8:3611, 29:2362, 33:769.
10 Safford: 8:3555-6; Navy biography; “Secrecy for Sale” and “Two Americans” chapters.
10 functions: 9:3962.
10 GI, GL: 36:91, 327.
10 division of cryptanalyses: 8:3560, 26:388, 10:4698.
10 Corregidor unit: 3:1559, 36:45, 61, 5:2425; Navy biography of Fabian.
10 Navy personnel: 4:1794, 8:3560, 26:388 for “young, enthusiastic, and capable.”
11 subsections and duties: 8:3572, 3611, 3895-6, 3936, 3574, 3576, 36:313.
11 Kramer: 8:3611, 3411, 3893-4, 9:4075, 36:72; Navy biography; George Morgenstern, Pearl Harbor: The Story of the Secret War (New York: Devin-Adair, 1947), 400.
11 Craig, Marshall attitudes: 3:1100-1, 1146.
12 cable companies’ refusal: 10:4676, 35:836.
12 95 per cent radio: 36:64, 312, 328, 37:1081.
12 Navy stations, Bainbridge duties: 8:3559, 3581, 3802.
12 kana, typewriter: 10:4705, 8:3579, 3394.
12 Army stations: 35:35, 37:1082-3; see also Harris, 333-335.
12 airmail: 8:3896, 35:82, 10:4720, 37:1082-3.
12 teletypewriter: 8:3559, 3805, for Navy, 35:106-108 for Army.
12 radio for PURPLE, RED, J 19: 8:3896, 36:47, 227, 311.
13 all but four: 6:2916. Less clear-cut figures at 10:5137, 11:5352, 37:1081-2.
13 Yoshikawa: Takeo Yoshikawa with Norman Stanford, “Top Secret Assignment,” United States Naval Institute Proceedings, LXXXVI (December, 1960), 27-39; Naval Intelligence and F.B.I, reports on Honolulu consulate espionage, PHA, 35:352-392, at 363, 431; 12:260.
13 telephone taps: 35:84, 36:222, 37:889.
13 Sarnoff, December 1: 33:856, 26:336, 36:163, 23:646, 653.
14 odd-even: 8:3923, 3900.
14 hierarchy: 33:1133-4 for an American formula.
14 variety of codes: 12:208, 35:403-409, 433, 439, 462-463, 676, 684.
14 priority schedule: 8:3395, 34:83, 36:311, 313.
14 LA: Code reconstructed by the author by comparing coded messages given in part 38 with solutions and translations in part 37. The year-end bonus message, for example, is 38:153 in code form, 37:983 in Japanese and English. My reconstruction is corroborated by an independent and much more complete one by Hardie, who has generously made it available to me. 36:68 for 1925.
15 PA-K 2 : Code reconstructed by the author in the same way, and corroborated by independent reconstructions by Hardie and by Howard T. Oakley. Hardie’s is especially complete. Yoshikawa message at 37:997, 38:172, 226. Cryptanalysts’ worksheets at 38:124, 237. Japanese keying instructions at 35:458-460. American names and times of solution at 4:1860-1, 10:4675, 35:103, 106, 36:67.
16 J series: Transposition method reconstructed by Hardie from key given at 37:1066 for message at 38:210-211, translations at 12:215 and 35:472, 679. Introduction and solution dates, 37:663, 12:310, 5:2082-3, 36:64, 67, 85.
18 J 19 vs. PURPLE percentages: 36:314.
18 PURPLE machine: reports of interviews in Japan by Bernard Krisher of Shiroji Yuki, Takeshi Kajiwara, Masana Horiuchi, and Hiroshi Hori, former code clerks, June 1963; report of interview by Shin Kawai of Kazuji Kameyama, May 1962; my Yoshida interview. PHA, 33:833 for general type; 12:209,35:673 for YU GO; 12:299 for plugboard; 12:1,3,137 for superencipherments; 8:3898 corrected 11:5309 for three-letter codewords; 34:84, 33:833, 12:7, 314 for RED. Interviews, Drs. Werner Kunze, May 4, and Rudolf Schauffler, May 6, 1962, German cryptanalysts who solved the RED machine. See also Farago, 78-81 for RED, 90-92 for PURPLE.
20 first essays: my suppositions.
20 codeword PURPLE: 1:258, 14:1401, 15:1423 for ORANGE; 35:47 for Holtwick.
21 “Most of the time”: Rosario Candela, The Military Cipher of Commandant Bazeries (New York: Cardanus Press, 1938), 25-26.
21 “When the PURPLE”: 34:84-85.
21 Friedman: “Two Americans” chapter.
22 techniques of soluti
on: my suppositions based on PURPLE’s cipher. See also Farago, 95-100.
22 mechanism: 3:1130, 9:4001.
22 first solution: 36:312, 34:84.
22 “Naturally”: 34:85.
22 captain of the team: 36:70.
23 breakdown: my suppositions; 34:34, 82, 36:312.
23 other PURPLE machines: 8:3561, 36:347, 34:85, 3:1197, 10:4773. See also Farago, 102, 253-254. 23 key prediction: 8:3778, 9:4005.
23 PURPLE + CA + K9: 12:8; IMTFE, Exhibit 808, for “highest type.”
24 balancing: 2:793.
24 “I see no use”: 7:3363. This was Vice Admiral William Ward Smith, who had had some experience in cryptology himself; see “Two Americans” chapter.
24 reasons for secrecy: 2:792, 907.
24 January 23 agreement: 2:788, 4:1734.
24 extra recipients: 5:2173, 2:464, 789, 790, 9:4033, 4529, 3:1196, 1151, 35:90, 16:2015, 34:93.
24 field commands excluded: Report, 181; 2:791-792, 3:1176-7, 6:2540.
25 July 8: 3:1212, 14:1326.
25 Philippines: 36:73, 61, 47, 4:1741-2, 10:4722, 4715.
25 COPEK cipher: 33:855, 863-864, 10:4717, 4831, 36:46. A photostat of the message of December 4 at 37:1065, marked “COPEK,” appears in Portfolio 5, Box 52, Records of the Joint Congressional Committee on the Pearl Harbor Attack, NA, RG 128.
25 McCollum letter: 10:4845-7.
26 serial numbers, July 19, December 3: 14:1398-9, 1408.
26 Memo 9, Watson, F.B.I.: 11:5475, 8:3725, 3:1147.
26 Thomsen: DGFP, XII, 661. See also Farago, 191-199.
26 messages of May 3, 5, 20, Nomura, June 23, November 25: 4:1861-3, 12:314, 35:671.
27 J 12, Code s: 9:3984 corrected 11:3510, 4:1863, 5:2070.
27 distribution procedures: 10:4723, 3:1100, 34:11, 8:3558-9, 3681, 3902, 9:4509, 4561.
28 “I intervened”: 3:1196.
28 pouches: 3:1324, 1575, 34:95, 8:3681.
28 surrenders key: 34:94.
28 Kramer explains, messenger stands by: 9:4109, 2:789, 3:1038, 4:1735.
28 departures from ideal: 3:1559, 8:3902, 29:2451.
28 advance telephoning: 8:3899-900.
28 “leave his office”: 34:45.
28 Hull, Knox, conferences: 9:4035, 4235, 8:3903, 5:2468.
28 copies returned, filed, burned: 2:447, 789, 3:1038, 9:3938, 4529, 29:2451, 8:3902, 36:345, 34:25.
28 bottleneck, increase, “most highly skilled”: 10:4275, 8:3896, 3400, 2:808, 4:1733.
29 year’s experience: 36:318.
29 telegraphic Japanese, “the so-called translator”: 2:808, 8:3400.
29 Mrs. Edgers, “not a reliable”: 36:303, 8:3446. 29 partial or no translation: 9:3947.
29 speed: 10:4723, 9:4600, 33:852.
29 volume: 35:25, 33:915, 848, 851, 37:1082, 1084-5.
30 winnowing: 29:2450, 10:4750-1, 34:11-13, 35:25, 8:3926, 3941, 9:3933, 4195, 4584.
30 Marshall complaints: 33:824, 3:1211, 1515.
30 pencil, clips: 4:1735, 1927, 5:2173, 9:4582.
30 twice a day, to homes: 8:3904, 11:5373, 8:3627, 10:4623.
30 exchange of messages, competition: 10:4927, 34:83, 8:3580, though denied 10:4740. Cooperation on a lower level was mandatory (37:1137).
30 hell, no hell: 29:2455, 3:1325.
30 White House distribution: 11:5475.
31 “witness,” “intensely interested”: 2:447, 11:5373.
31 most reliable: 2:792.
31 15 per cent: 4:1977.
31 USAFFE command: 29:2452.
31 speedily: 3:1147, 1196.
31 “priceless asset”: 3:1362.
31 “too much of it”: 33:824.
31 “This time”: Shigenori Togo, The Cause of Japan, translated by Fumihiko Togo and Ben Bruce Blakeney (New York: Simon and Schuster, 1956), 61.
32 Proposal B, “final,” “because”: 12:96-7, 99, 100.
32 dummy traffic: Lord, 17; PHA, 11:5356, 1:185, 238.
32 Circular 2353: 12:154.
33 “There are reasons,” “Tokyo time”: 12:165, 173.
33 Kochi: Lord, 21.
33 telephone open code: 12:178 (more clearly at 35:652), 188-91.
37 INGO DENPO: 12:186-8, 35:669.
37 translation of HATTORI equivalent: 36:308, 341-2, 35:678, 33:862.
38 solved November 28: Translation dates are given at foot of each intercept.
38 winds intercept efforts: 10:4700, 4706-7, 18:3304-6, 26:393, 35:83, 8:3915.
38 swamping: 8:3924, 9:4145 corrected 11:5312, 26:393.
38 “Should Japan,” “Say very secretly”: 12:202, 204.
39 F.D.R.: 9:4072.
39 call-sign change: 17:2601, 2636, 10:4680.
39 November 1 change: 37:754, 23:664, 10:4903, 6:2522, 26:866. The October 31 date is Hawaii time; it was November 1 in Japan.
39 like July and February: 10:4833, 4839.
39 “Admiral Kimmel said”: 36:128.
40 O.N.I, report, “dotting i’s”: 15:1896, 10:4892.
40 new security measures, Rochefort spots: 10:4893, 36:37, 128, 17:2635-6, 37:745,756.
40 December 2 and 3 summaries: 17:2638-9. Layton’s testimony before the Congressional committee, especially at 10:4829-42, 4892-4, and 4903-4, and Kimmel’s remarks at 6:2523, are very enlightening about the limitations of traffic analysis. Ironically, Rochefort’s unit had detected on November 3 the creation of the 1st Air Fleet (37:755)—the Pearl Harbor strike force—but was unable to follow it further.
40 code-destruction messages: 12:137, 208-209.
41 “Climb Mount Niitaka”: 13:713, 426, 1:185, 216; Robert J. C. Butow, Top and the Coming of the War (Princeton, N J.: Princeton University Press, 1961), 370.
41 F.B.I, taps: 35:48, 36:222, 336.
41 “At 4 p.m.”: 35:205-206.
41 Circular 2445: my composite of 12:215, 35:472, 679.
42 sends HARUNA: 38:250.
42 Tsukikawa: 35:363.
42 Kühn: 35:320-322; Ronald Seth, Secret Servants: A History of Japanese Espionage (New York: Farrar, Straus & Cudahy, 1957), 9-10.
42 signal system: 12:267-268, 35:221-322, 38:158, 161.
42 Street gives Mayfleld: 36:243, 331-332.
43 “burn all”: 12:215.
43 “chances had diminished”: 2:503.
43 F.D.R.: 11:5284 corrected 5513.
43 embassy, Robert, paper codes, destruction: Yoshida, Kajiwara, Hori; PHA, 9:4576.
44 Iguchi and code clerks: IMTFE, Exhibit 2967, affidavit of Shiroji Yuki.
44 HARUNA messages: 5:2077.
44 “If you rupture”: 9:4226.
45 “Highly reliable,” “Circular 2444”: 14:1407-8.
45 meaning of “PURPLE”: 10:4842, 36:136.
45 “Memorize,” “Destroy this system”: 14:1408-9.
45 false winds execute: 33:839-840, 8:3386-7, 18:3305, 3320. This is the execute which Safford thought to be true.
46 Liaison Conference: Togo, 199; Butow, 372-374.
46 “that the high command”: Togo, 208-209.
47 Yoshikawa messages and errors: 12:266, 268; 35:388-389.
47 Kase, Koshi: 13:427-428; Lord, 25.
47 redrafted, special frequency: comparison of messages; my supposition.
47 10 per cent, “not … vital,” December 4, 8: 18:3335-6; 26:220, 10:4674.
47 “Five numeral”: 37:1065.
47 flag officers’ system unsolved: 18:3335-6.
48 Mayfield gets second batch: 23:673, 36:224, 263, 331.
48 hard to say No: Dyer, interview, December 12, 1963.
48 Woodward, Dyer, Wright: 36:262, 319, 323; Navy biographies.
48 Radio Intelligence Publications: 36:38, 10:4677.
48 1:30, 12-hour days, “nothing but junk”: 36:319-20, 322, 37:983.
48 Mori: 23:360, 30:2979-81; Lord, 5-6.
49 pilot message: 12:238-239, 9:4510-13.
49 S.I.S. closed, reopens: 35:107, 36:315, 8:3558, 9:4001, 10:4927.
50 Navy handles: 8:3558.
50 “At first glance”: 36:303, 345.
50 parts 1 and 2, Cave: 8:3576, 36:314-315, 37:1084.
50 3 p.m., part 8: 8:3898,11:5509.
50 Linn clears garbles: 8:3562.
50 6 p.m., parts 9 and 10:8:3906; 14:1414-15 shows only these parts decoded by Army.
51 7:30: 8:3899.
51 garbles left: 12:240-245. Correct plaintexts from original document as handed to Hull, NA, RG 59.
51 Terasaki party: Yuki affidavit and interview; Butow, 379; Wohlstetter, 207.
51 9 p.m., 10 hours: Joseph C. Grew, Ten Years in Japan (New York: Simon and Schuster, 1944), 497.
51 Mori tap and transcript: 23:640, 26:360, 27:737-739, 29:1666, 36:223.
52 “very suspicious”: 28:1542.
52 Yomiuri feature: Lord, 211.
52 6:01 p.m. message: 12:270, 35:453, 390, 38:149, 233.
52 Kramer prepares folders, begins rounds: 8:3899-901.
53 Schulz, F.D.R.: 10:4659-65.
54 Knox: 8:3902-3, 9:3991, 4514; Report, 432-433.
54 Wilkinson’s home: 9:3903, 10:3993, 2:925.
54 back to Navy Department: 9:3904.
54 “cage,” Martin: 35:107-108; 12:270 shows message marked “2-TT” indicating teletype from Post 2.
55 looking for 14th part: 10:4642, 4932; 8:3575.
55 Serial Nos. 380, 381: 33:765.
55 an hour to break: 33:845.
56 barrage balloons, final messages: 12:269; Lord, 25-26.
56 Ono, bits of paper: Lord, 25, 35.
56 Kramer arrives, smooths copy, delivers: 9:4006, 4043, 8:3907, 3393.
56 Beardall, F.D.R.: 11:5282-3, 5273-4.
57 14th part at State: 9:4046-7, 4545, 16:2015.
57 9 a.m., “stunned me”: 9:4517. An unsolved question is why this message remained in S.I.S. at least two and probably four hours, when it would have required only five to ten minutes to translate (8:3785). Brotherhood brought the message to S.I.S. for translation probably a little after 5 a.m., but no later than 7 a.m. (33:844). Yet it had not come back to GZ by 9:30, when Kramer left to deliver the 14 parts, nor to Bratton by 8 a.m., when he had arrived at his office (9:4516). The earliest reference to it after Brotherhood’s is Bratton’s seeing it at 9 a.m. I have been unable to discover any reason for the delay. Would speed have averted Pearl Harbor? Possibly, but I doubt it. A translation on Bratton’s desk by 8 a.m. might have enabled him to catch Marshall before his Sunday morning horseback ride and perhaps get a warning out much earlier. But then there is no reason to believe that R.C.A. in Honolulu would have delivered it any sooner than it did. Stark had not wanted to send another warning on the basis of this intercept, and his seeing it at 8 a.m. instead of at 9:30 probably would not have changed his thinking. Surprisingly, neither the Congressional committee nor its staff nor any writers on the attack ever noticed this hiatus.
