Jiang Ziya's little secret! Did the small token help King Wu defeat King Zhou?

Communication in war is an extremely important link. If communication is not smooth, it will be difficult to effectively coordinate between the front and rear, between superiors and subordinates, and between friendly troops. At the same time, confidentiality in communication is also very important: once the intelligence is intercepted by the enemy, it will bring disaster to the front troops.

Image source: soogif

Therefore, today's military communications are almost all carried out through telecommunications with the help of cryptographic technology. So, in ancient times when there was a lack of electronic equipment, how did the military transmit information reliably and confidentially?

01 Yin Fu: Jiang Ziya’s little secret

In ancient times, military communications were first transmitted in plain text: the sender wrote the military report and sent it to the recipient through a messenger (or postman). At this moment, if the messenger was intercepted and killed halfway and failed to destroy the letter in time, the military report would inevitably be leaked.

To this end, the ancients also thought of many strange ways to keep secrets. For example, it is said that Jiang Ziya came up with the idea of ​​using the "Yin Fu": before the generals went out to fight, they agreed with the monarch to use the length of the token to represent the battle situation: if the war went smoothly, they would send back a 1-foot-long token; if the war was stalemate, they would send back a 7-inch-long token; if the token was only 3 inches long, it meant that the war was a complete failure and reinforcements were needed! There was no text on the token, so the enemy would not be able to understand it even if they intercepted it.

However, the information that this Yin Fu could convey was too thin. Later, Jiang Shang came up with an improved version of the Yin Fu: in ancient times, letters were written on bamboo slips and bound into a roll with ropes for reading. For this Yin Fu, after writing, the bamboo slips were disassembled and shuffled, and then handed over to two or three people to pass on separately.

In this way, even if one of the bamboo slips is stolen, the full text cannot be guessed. The recipient can read the full text by correctly arranging the bamboo slips according to the secret marks on the back of each bamboo slip. This method is found in the ancient military book "Six Strategies" and is quite credible.

02 Riddle: Riddles on paper

In the era of paper use, Yin Fu's tricks were no longer effective, and the means of encrypted communication were also updated accordingly.

A common technique used in the Song Dynasty was called "word verification", which meant that before sending troops, the generals and the monarch would secretly agree to use a poem as a communication medium, with each word in the poem representing a specific meaning.

For example, in the poem "The country is broken, but the mountains and rivers remain. In the spring, the grass and trees are deep in the city", the word "country" means "many enemies", "broken" means "not many enemies", "mountain" means "need for food and grass", and "river" means "sufficient food and grass"... When it is time to report, the generals will write this poem, and then put an ink dot on one of the words, and the monarch will know what it means. This agreement is only known to the generals and the monarch. Others who received the letter are completely unaware of it.

Image source: Made by myself

Another way to hide information is called "Fanqie". In modern Chinese, there is the concept of pinyin, that is, the pronunciation of each word can be divided into initial consonants and final vowels. After the Han Dynasty, "Fanqie" was used to represent initial consonants and final vowels. In this way, the two parties in communication can agree on two lines of poetry. In the first line of poetry, each word corresponds to an initial consonant; in the second line of poetry, each word corresponds to a final vowel. These two lines of poetry are the "code book" for communication.

For example, "the moon shines brightly before the bed" is represented by the initial consonants, and "the old man in a straw hat and raincoat on a lonely boat" is represented by the final vowels. Then the "four two" written in the letter represents the pronunciation of "have", and "two one" represents the pronunciation of "interest", and when read together they mean "interesting".

Image source: Made by myself

Of course, these two lines of poetry were only available to generals and monarchs. Others would see a bunch of numbers and would be completely unable to interpret them. Qi Jiguang, a famous general who fought against Japanese invaders, was well versed in this and was said to have compiled a book called "Qi Jiguang's Eight-tone Word Meaning" to explain this.

03 Hidden Head: More Like a Word Game

The information that word verification can convey is still too limited. Fanqie is too laborious to read, and the fanqie itself is not precise, which can easily cause confusion. For example, the fanqie of "将" and "墙" are the same, but their meanings are very different.

In addition, the ancients came up with a secret writing method called "writing on silk with alum", which is to use alum solution as ink and write on silk. After drying, the writing disappears; and the recipient gently soaks the silk in water, and the writing will reappear. However, once this method is discovered, the secret will be lost in an instant.

Therefore, the ancients came up with the "leak hole" method to encrypt information. The principle comes from the familiar "hidden head poem": in a poem, take the first word of each sentence and connect them into a sentence, which is called "hidden head". However, this encryption method is also easy to be discovered, and the upgraded method is "leak hole".

The two parties in communication each hold a piece of the same thin sheet (it can be a jade sheet or a copper sheet) with several small holes cut out on it. When writing a letter, cover the thin sheet on the white paper, fill in the small holes with the words you want to say, and then fill in some irrelevant words in the other blanks. When receiving the letter, cover the thin sheet and only read the words exposed in the small holes, which is the message to be transmitted. And this information is hidden in a large piece of messy Chinese characters, and it is impossible to guess without this thin sheet.

For example, the letter in the picture below looks like just some commonplace conversation; but if you use the hole plate next to it to decipher it (the white circles represent the holes), what can you read out? You can give it a try.

Image source: provided by the author

04 Beacon (suì): a large password

As we all know, beacon towers are used to transmit military reports. The presence of beacon fire or wolf smoke indicates that the enemy is attacking. However, beacon towers can actually transmit a lot of information, and it is encrypted!

Image source: Pixabay

In the Han Dynasty, beacon towers were called "Fengsui", where "Feng" refers to flames and "Sui" refers to thick smoke, and there is a clear distinction between the two. On a beacon tower, the number of "Feng" and "Sui" has different meanings according to the arrangement and combination, which is called "Pin Yue".

For example, if the soldiers on the beacon tower discovered that there were about a thousand enemies attacking, they would use "three beacons and two fires" to indicate it during the day; and at night, they would use the combination of the number of flames on the beacon tower and the number of flames under the beacon tower to indicate it.

In addition, the beacon towers of the Han Dynasty would use "Peng" to transmit signals during the day. That is, a piece of red or white cloth would be hung high on the mast. The "red" and "white" here, like flames and wolf smoke, also transmit signals through permutations and combinations.

The above-mentioned "pinyue", that is, the fixed meaning of each group of signals, is usually only known by the deputy commander of each beacon tower, and the soldiers can only obey orders and implement them, and outsiders have no way of understanding them. In this way, the beacon tower has become a huge encrypted communication method.

In order to secretly transmit military reports, the ancients came up with many interesting methods, which maintained peace on the border for a long time.

Source: Chongqing Science and Technology Museum

Author: Mantou Laoyao, popular science writer, PhD in Chemistry from Nanjing University

Review experts: Huang He, Li Chunli, Xu Xiaoping

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