Decipherment · June 1916

Rongmi (容密): fourteen telegrams and their key

Fourteen cipher telegrams exchanged in June 1916 between Tokyo and Shanghai around Huang Xing and Zhang Xiaozhun: buying arms in Japan for Zhejiang, loans, and negotiations with Beijing after Yuan Shikai’s death. A single key reads them all.^[27]

Grid reading order: Brice Dudout. Transcription of the continuation sheets, key recovery, translation and probable readings: Claude (Anthropic). All digits re-read by Brice Dudout. Starting model (four digit substitutions): Codex’s trials.

The key is a reconstruction, not taken from a historical code book. Translations are working proposals; probable readings are shown beside the decoded text, never in place of it. Identifications of people are candidates, with their source.

The key

Sheets are read in columns, right to left and top to bottom (reading order proposed by Brice Dudout), in groups of four digits; the public prefix 1369 1378 = 容密 stays in clear. For each group C: replace each digit using the table for its place, then compute P = (σ(C) + 0901) mod 10000 by ordinary addition with carries; P is the character number in the Chinese Telegraph Code (CTC).

Digit read	0	1	2	3	4	5	6	7	8	9
thousands	0	1	2	3	4	5	6	7	9	0
hundreds	0	1	2	3	4	5	6	7	8	9
tens	0	1	9	8	2	7	6	5	4	3
units	9	8	0	1	7	2	3	4	5	6

No group starts with 00: the encipherer writes 90. Example: σ(2081) = 2048 (tens 8 → 4, units 1 → 8), + 0901 = 2949 = 款.

The key was recovered on four telegrams (N02, N08, N11, N12), then read the other seven without refitting; refitted on the whole re-read corpus (590 groups), it returns exactly the same tables. Only the “90 = 00” rule was added afterwards, from all groups beginning 90.

In the proposed reading, {x} replaces an anomalous decoded character with a probable reading; the note says whether a variant of the cipher group differing by a single digit gives that character, or whether it is a contextual reading. 〔x〕: character kept, unresolved.

Another reading of the key: a renumbered 明密 codebook (S. Tomokiyo)

This interpretation is due to S. Tomokiyo (Cryptiana, 23 October 2026)^[22]. He suggests that the clerk did no arithmetic: he used a copy of the “明密” code whose page, column and row numbers had been rewritten by hand for secret (密) use; he illustrated each key on a June 1916 edition of the 明密碼電報書 in his possession. Our formulae describe the same table by calculation.

Pages numbered cyclically from page 10: written page 01 = 10, 02 = 11, …, 79 = 88, then 81 = 00, …, 90 = 09. The “+ 0901” of our formula is this page shift plus one row. The only difference is written page 80: 89 according to S. Tomokiyo, 99 by our formula. The only group concerned, 8012 (N25), read in neither case (9911, not in the table; 8911 窔), as S. Tomokiyo noted. With two adjacent digits swapped, 8102 gives 一, hence “一切到乞賜教”: the reading of N25 is corrected accordingly. S. Tomokiyo’s simpler cyclic numbering is the more probable.

Written digit	0	1	2	3	4	5	6	7	8	9
column	0	1	9	8	2	7	6	5	4	3
row (1–10)	10	9	1	2	8	3	4	5	6	7

Check: for all 10,000 group values, the published key splits exactly into page (first two digits), column (tens) and row (units), with no residual carry (mingmi.py). In the book each column holds xxx1 to xxx9 and then, at the bottom, xxx0: this is what our “carries” expressed.

S. Tomokiyo also notes that many “X密” codebooks of 1913–1923 are preserved in Taiwan; many probably differed only in such numbering.

Context

The dated telegrams run from 9 to 16 June 1916, just after Yuan Shikai’s death (6 June). Zhejiang, whose military governor Lü Gongwang took office on 6 May, is trying to buy arms in Japan; Zhang Xiaozhun (courtesy name 潤農), in Tokyo with Huang Xing, leads the talks (N02, N08, N12, N14) and reports to Huang Qun (溯初, N11) and Jiang Fangzhen (百里, N19a, N28).

From Shanghai, Yin Ruli, Ge Jing’en and Huang Fu (abbreviated signature 驪郛恩) relay Lü Gongwang’s questions (N21, N25, N36) and report to Huang Xing on the dealings with Beijing (N24): Li Yuanhong invites the Shanghai notables; Tang Hualong (濟武), Gu Zhongxiu (九峯), Zhang Ji (溥泉) and Fan Yuanlian (靜生) are approached; the condition set is the repeal of Yuan’s laws and a return to the 1912 Provisional Constitution, restored on 29 June.

Two more Rongmi telegrams from late June, intercepted and filed in the next volume (V4B, V4D), and a Gongmi of 2 July (V4E) read with the same keys without refitting: the arms purchase continues (Aoki, Takakura), Yin Ruli and Li Shucheng leave for Beijing, and Duan Qirui reverses himself on the procedure for restoring the Constitution.

N14

47 groups · Date: June 9, 1916 · Direction: Tokyo → Shanghai · 4 sheets · digits re-read by Brice Dudout

Huang Xing to the Zhejiang governor after Yuan’s death: the arms go first, the one-million loan will follow.

Raw decoding, uncorrected

轉呂都督鑒袁死大局益艱非切實預備不足以申張國法奠定國基感佩藎籌當効棉力械先運款百萬亦可卽成興佳

Proposed reading

轉呂都督鑒：袁死，大局益艱，非切實預備，不足以申張國法、奠定國基。感佩藎籌，當効棉力。械先運，款百萬亦可卽成。興佳

Translation

To be passed to Governor Lü: Yuan is dead and the general situation is harder. Without serious preparation we cannot uphold the law of the State and lay its foundations. Grateful for your devoted plans, I shall give my modest strength. The arms will be shipped first; the one-million loan can also be concluded at once. — Xing. The 9th.

Forms and JACAR sources

N14-1 · B03050089300 PDF 7 L · JACAR · scan

N14-2 · B03050089300 PDF 8 R · JACAR · scan

N14-3 · B03050089300 PDF 8 L · JACAR · scan

N14-4 · B03050089300 PDF 9 R · JACAR · scan

Digits and CTC, group by group

#	C	CTC	Char.	Sheet
prefix	`1369`	`2267`	掽	N14-1
prefix	`1378`	`2256`	揜	N14-1
1	`5669`	`6567`	轉	N14-1
2	`8813`	`0712`	呂	N14-1
3	`5879`	`6757`	都	N14-1
4	`3308`	`4206`	督	N14-1
5	`6105`	`7003`	鑒	N14-1
6	`5015`	`5913`	袁	N14-1
7	`2036`	`2984`	死	N14-1
8	`0241`	`1129`	大	N14-1
9	`0586`	`1444`	局	N14-1
10	`3297`	`4135`	益	N14-1
11	`4441`	`5329`	艱	N14-1
12	`6398`	`7236`	非	N14-2
13	`8596`	`0434`	切	N14-2
14	`0427`	`1395`	實	N14-2
15	`6417`	`7315`	預	N14-2
16	`8352`	`0271`	備	N14-2
17	`8104`	`0008`	不	N14-2
18	`5424`	`6398`	足	N14-2
19	`8200`	`0110`	以	N14-2
20	`3089`	`3947`	申	N14-2
21	`0844`	`1728`	張	N14-2
22	`9084`	`0948`	國	N14-2
23	`2249`	`3127`	法	N14-2
24	`0278`	`1156`	奠	N14-3
25	`0475`	`1353`	定	N14-3
26	`9084`	`0948`	國	N14-3
27	`0117`	`1015`	基	N14-3
28	`1081`	`1949`	感	N14-3
29	`8270`	`0160`	佩	N14-3
30	`4770`	`5660`	藎	N14-3
31	`3725`	`4693`	籌	N14-3
32	`3032`	`3981`	當	N14-3
33	`8601`	`0509`	効	N14-3
34	`1874`	`2758`	棉	N14-3
35	`8520`	`0500`	力	N14-3
36	`1880`	`2750`	械	N14-3
37	`8482`	`0341`	先	N14-4
38	`5765`	`6663`	運	N14-4
39	`2081`	`2949`	款	N14-4
40	`3203`	`4102`	百	N14-4
41	`4603`	`5502`	萬	N14-4
42	`8158`	`0076`	亦	N14-4
43	`8764`	`0668`	可	N14-4
44	`8715`	`0613`	卽	N14-4
45	`1173`	`2052`	成	N14-4
46	`4332`	`5281`	興	N14-4
47	`8265`	`0163`	佳	N14-4

N19b

143 groups · Date: June 11, 1916 · Direction: Tokyo → Shanghai · 12 sheets · digits re-read by Brice Dudout

Huang Xing to the Shanghai senders (reply to the 8th and 9th): yes to the 1912 Constitution and Parliament, but nothing without armed force; Zhejiang must be the pillar of the South-East; Lu Rongting and Li Liejun should march on Hubei and Jiangxi; Japan will not lend to Beijing before unification.