"If you look closely at the drawings, there is a good chance that the clues to unlocking the code are on the drawings. ”

Xie Lang, who was sitting at the desk, flipped through the sixteen-page drawings one by one, and there was nothing on them except the structural drawings of the machine and the corresponding text descriptions.

"Password...... Four-digit ......"

She inadvertently turned over a drawing, and there was no word on the back of the yellowed page, and there seemed to be a dark mark on it, I don't know if it was accidentally stained.

"Wait. Xu Chunqiu made a false block on her wrist and motioned for her to stop.

"What's wrong Qiuqiu?"

Xu Chunqiu quickly flipped through another drawing, and the back of the yellowed page also had a dark trace, which was not a stain, let alone a coincidence.

Xie Lang's eyes widened after that: "...... This is!"

Here comes the clue.

Xie Lang and Xu Chunqiu hurriedly turned over all the drawings, and for a while they were excited to raise dust everywhere.

There wasn't enough space on their desks, so they put the drawings upside down on the floor, stitching them together in the order of the page numbers.

On the back of the drawing, a series of symbols of unknown meaning are connected - "〡〩〣〧".

The little flame of hope that Xie Lang had finally ignited in her heart was extinguished, she didn't see the reason for it for a long time, and flattened her mouth a little frustratedly: "What is this......?"

"It's Suzhou yards. ”

Almost at the same time as she said this, the voices of the two people blurted out in unison.

One is Xu Chunqiu, and the other is Du Zigui.

Suzhou yard, also known as grass code, flower code, Fanzi code, business code, is the early Chinese folk "commercial number", often used in pawnshops, pharmacies and other occasions.

This special counting method originated in Suzhou, China, which was born out of the historical arithmetic of Chinese culture, and is the only arithmetic system still in use, and even today, Suzhou yards are still occasionally seen in the streets of Hong Kong and Macau, old-fashioned tea restaurants, and many Chinese medicine pharmacies.

Du Zigui is a southerner, he was born in Suzhou, the birthplace of Suzhou yards, when he was a child, the master who studied opera is old, and his health is not very good, he grabbed medicine for the master when he was a child, and often went in and out of the Chinese medicine pharmacy, so he is quite familiar with this symbol.

And what about Xu Chunqiu? Why did she recognize this old-fashioned counting system?

Du Zigui's searching gaze fell on Xu Chunqiu's face, and Xie Lang was also curious.

Xie Lang's round and blunt apricot eyes widened, and she felt that Xu Chunqiu was simply omnipotent: "Qiuqiu, do you still recognize this?"

Xu Chunqiu nodded humbly and replied very measuredly: "I understand a little bit about it." ”

In fact, she only knows a little bit about this kind of symbol.

Just as Roman numerals originated from Rome and were called "Roman numerals", Suzhou yards were named "Suzhou", but in fact its connection with Suzhou is not as close as people think.

Suzhou code in business, finance, as well as the lives of ordinary people, especially the use of vertical ledger in the bookkeeping is widely used, because of its strong image, even the people of Li who are not highly educated, can also smoothly grasp and write proficiently, in a sense it is also a kind of "market text".

Xu Chunqiu had lived in that era, how could she not recognize this age-old counting system.

Lu Xiu, who was standing on the side, immediately reacted with enlightenment the moment Xu Chunqiu said the words "Suzhou yard".

His initiation was not due to his knowledge of the four symbols written on the back of the drawings, although he also had memories of that era, but at the beginning of the last century, due to the continuous invasion of foreign capital, the old banks gradually shrank, and were replaced by the vigorous development of a large number of new banks, and this old bookkeeping method was gradually replaced by foreign inflows from overseas.

The account books of the Lu family trading house are all Western-style bookkeeping methods, and the young master Lu rarely comes into contact with the small merchants and vendors on the streets, so he is far less sensitive to this kind of hieroglyphs than Xu Chunqiu.

It was something else that struck him suddenly.

The four-layer bookshelf placed by the program team against the wall was not completely useless, and when Du Zigui tried to unlock the password lock of the time machine with the number of books placed on each shelf, Lu Xiu's eyes were also locked on the dusty bookshelf.

His gaze swept over the spine of each book, and the shelves were very varied and illogically arranged, with Marx's Capital and Dostoevsky's Crime and Punishment lying on the top shelf, and Confucian classics such as the Analects and Mencius and Yan Fu's The Theory of Heavenly Evolution were closely placed side by side, quite a bit of a mix-and-match.

And the last layer ......

Wait, what book does he remember?

Lu Xiu strode to the bookshelf and pulled out the thin booklet, the book was very thin, the title could not be written on the spine, and the gilded title could only be printed on the hard cover - "Suzhou Code Comparison Table".

Just as he opened the comparison table and was about to compare the symbols on the back of the drawing with the numbers on the comparison table, Xu Chunqiu spoke without pause.

“1937。 "The password is 1937." ”

Lu Xiu silently put the comparison chart back on the shelf, and Du Zigui looked at Xu Chunqiu with more and more surprise.

He is a native of Suzhou, when he was a child, he dealt with these symbols in the Chinese medicine pharmacy every once in a while, so many years have passed, and now he suddenly sees the Suzhou yard, and he still needs to react for a while, but Xu Chunqiu can blurt out directly without hesitation.

Du Zigui remembered Xu Chunqiu's modest answer to Xie Lang, and there was only one thought left in his mind, this is not just "a little bit of understanding", it is obviously so proficient that he can't be more proficient, okay?

Fu Nanxun got up and entered the string of numbers into the password disk next to the handle of the time machine, and a crisp prompt sound came from the door lock, "Unlocked successfully".

A voice came from inside the huge iron box, and Xu Chunqiu reminded from behind, "Teacher Fu took a step back. ”

Fu Nanxun subconsciously did so.

The originally locked iron door slowly swirled outward, stopping just an inch in front of Fu Nanxun's chest.

His eyes lit up, and almost at the same time as the door opened, he turned his head to ask Xu Chunqiu's opinion: "Shall I go in first to take a look at the situation?"

Xu Chunqiu nodded slightly, but his brain was still running rapidly.

The time machine was opened, but I always felt that this secret room was so easy for them to leave.