Donald Thomas - Sherlock Holmes and the King’s Evil

I worked my way through it, trying to pick out any groups of letters whose position or repetition might help us to “get a lever” under the rest. Holmes took another approach.

“We know that Eckhardt in Mexico City must be able to decode it. It has been sent as a matter of urgency and therefore probably in a code that can be read by anyone who knew the previous one. Eckhardt is not allowed to refer the matter to his underlings, he can ask for no assistance, therefore it must be a familiar system to him.”

He bowed his head over the paper, the harsh white gaslight throwing the shadow of his aquiline profile on the wall. Presently he chuckled. His pencil was ticking the most frequently used words. He selected one of them.

“Here, here, and here, Watson. The group of numbers most frequently used is 69853. From its position, as compared with earlier messages which we have decrypted, it appears to be a noun, almost certainly a proper name. In an urgent and secret diplomatic message to the German Minister in Mexico City, what is that word likely to be?”

“I would say most probably ‘ Mexico.”’

“And here it is used with the cipher 5870, which also occurs just before it and immediately after it. The same 5870 occurs again two words further on. May I be kicked from here to Charing Cross if that is not a comma! What else can it be with such frequency? Now, such a series of commas would suggest a list, would it not? A list of three items in this case, the second of which is in two words. The second of those two words is ‘ Mexico.’ So we have a compound noun, the second half of which is ‘ Mexico.’ To me that strongly suggests ‘ New Mexico.’ Let us see.”

It was a characteristic leap of intuition. Beforehand the answer might have appeared an outside possibility. As presented by Holmes, it now seemed the only answer that made sense.

“In all probability it is a list of American states,” I said quickly.

“Excellent, Watson. New Mexico, with an item before and an item after. The one in front of it appears as five letters. Try “ Texas.” The one that follows it has four syllables. What state associated with Texas and New Mexico has four syllables?”

“ Arizona?” I replied hopefully.

“And what unites Texas, New Mexico, Arizona? All three were at one time part of Mexico and were lost to the United States by conquest. What plan has Herr Zimmermann for those states now?”

“To return them to Mexico? Impossible!”

“Not at all impossible, provided that there is a sufficient bargain upon the table. Another name 52262 recurs closely. You will recall that all nations in the last diplomatic cipher to be broken by us were reduced to five digits and I fancy this is one of them. Allow me the luxury of supposing that it stands for “ Japan.” You will recall that the battle-cruiser Asuma lately paid a prolonged courtesy call to Mexico, as the papers tell us. That news was contained in one of Bernstorffs previous ‘appreciations’ of the war situation. The ship was in Turtle Bay so long that she ran aground and had to be attended by other units of the Japanese fleet.”

“What about the United States?” I inquired cautiously, “Surely a more likely country to be mentioned than Japan in the context of Mexico?”

“Not quite in the proximity which we find here. If my instinct is right, this telegram is about the part to be played by others in respect of the United States. In that case, ‘ United States ’ may have a lower frequency than the protagonists. You will find 39695, here, and here, and here, occurring almost incidentally. That I deduce is more likely to be the United States. I shall be surprised if I am not right.”

We worked long into that cold January night, deaf to the sounds of the street below, indifferent to the supper which Mrs Hudson brought on a tray and which remained untasted.

“Yes, yes!” said Holmes impatiently to her kindly reproach. Presently the sitting-room air was clouded with the smoke of his pipe and the food still remained almost untouched.

I was little help, I fear. Yet I could not have torn myself away as I watched him working at the blocks of numbers on the telegram form. He had the previous cipher of the German diplomatic telegrams to hand and now established to his own satisfaction the five-number groups which represented the nations, like pieces on a chess-board.

As the hours passed, Zimmermann’s text began to appear in groups or clumps of letters and signs, like islands in a sea of numbers. Just after midnight, Holmes hit another vein of inspiration. Nouns were divided into groups of four or five letters. Other words varied a little to identify each occurrence. He made out that 6926, 6929 and 6992, were varying forms of “and,” determined by which letter began the next word. This in turn gave him the first letters of “ Japan,” “understanding” and “suggestion.” With fewer than half the words deciphered, the purpose of the telegram was plain. He recognised 5903 as “krieg” or “war.” A repetition of 98092 from an earlier telegram gave him “U-boat.” This left him with an incomplete phrase, “ersten 13605 un-14963 U-boot krieg.”

“What is the date, Watson?”

I was quite unprepared for this and had to think for a moment.

“The twenty-third of January. That is to say, the small hours of the twenty-fourth.”

“Admirable! Then the crucial date in the telegram must be ‘ersten Februar’-the first of February! The first of the next month in the immediate future. One does not use telegrams for dates that are far off, there is no urgency and the decision may not yet have been taken. Therefore we have, The first of February un-14963 U-boat war.’ There is already a U-boat war being fought but what is to come is in some way different. What can that be but ‘The first of February un-restricted U-boat war.’ It is an instruction to Bernstorff in Washington and an order to Eckhardt in Mexico City, to the effect that Germany will sink on sight, in a week’s time, neutral shipping entering European waters.”

“ Wilson cannot hold back from war, if that is the case!”

“I fear he may. The decision lies with Tirpitz and his master. If the Germans use the threat sparingly, Wilson will hesitate to commit his country to all-out war. Who would not? The loss of a few ships is nothing compared to a million men slaughtered on the battlefield and the nation’s prosperity in ruins. In any case, the likely outcome is that neutral vessels will keep well away from our shores, our own merchant fleet will be destroyed by Germany ’s torpedoes, and our goose will be cooked. That is the plan in Berlin. They want to preserve peace with America, if they can. If not, they hope to trap her in a war on her own continent.”

By three o’clock in the morning his pessimism seemed confirmed. We now had a translation of the text of the earlier passage: “Zimmermann to Bernstorff. Strictly Secret. Decipher this yourself. We intend to begin unrestricted U-boat warfare from 1 February. We will attempt to keep the United States BLANK. If this should not be BLANK, we offer Mexico…”

“The first BLANK is ‘neutral’” I said, “the second is ‘possible.’”

The rest of that night was spent in teasing out from the sets of numbers just what it was that Mexico might be offered in exchange for a German alliance. We made out “united in war, united in peace.” Then we returned to “ Texas, New Mexico, Arizona ” and the single word “zuruck”-“back.” Preposterous though it might seem, President Carranza was being offered the return of Mexico ’s lost territories in return for loyalty to the Kaiser.

This reading was confirmed when Holmes deciphered the two occurrences of 22464 as “President,” referring to President Carranza of Mexico, who was to be both a German ally and mediator in the alliance. He must induce 52262- Japan -to join the pact. England, which now appeared for the first time, would be “compelled” to make peace in a few months by a massive U-boat assault now being prepared. This would be sustained by supplies and fuel from Mexican ports. So long as the United States had only its small peacetime army, it could be invaded along the Mississippi valley by a Mexican army with the support of German “legionaries” and Japanese troops, conveniently cutting off those territories which were now to be returned to President Carranza. It was a complete confirmation of the tall story I had heard in the Army and Navy Club several years before!