Afterwards, they searched for many books that were easily found, trying to decrypt the code using this method, but they all failed.

Song Tingfeng and Zhu Guangxiao were a bit disappointed. Song Tingfeng narrowed his eyes and said, "Ning Yan, you suddenly became less intelligent."

It was obvious that Xu Qi'an's thinking had significantly declined, and he wasn't as sharp as before.

Xu Qi'an raised his head and stared blankly at the crisscrossing beams, saying irritably, "During those days when your friend was unwell, were you also particularly lacking in energy?"

"Why, why are you bringing up my friend again..." Song Tingfeng felt a little embarrassed.

"Hehe." Xu Qi'an thought to himself, I haven't slept for thirteen days, how can you expect my brain to work quickly? That useless Su Su can't even help me stay awake, what's the point of keeping her?

However, the advantage of this "Mei" was not in its core, but in its accompanying shell.

Keeping a "Mei" was equivalent to keeping a fish pond, which was more relaxing and comfortable than taking care of Huai Qing, Lin An, Fu Xiang, and Cai Wei, who were just backup options.

At that time, Xu Qi'an, the owner of the fish pond, would hold a steel fork and quickly and accurately stab whichever fish he chose.

"Let's take a break." Song Tingfeng suggested.

"Ask the postman to bring some sweets." Xu Qi'an said.

The best way to combat mental fatigue was to consume sugar. Sugar was the brain's only usable source of energy. Most people liked to eat sweets not because they tasted good, but because the brain prompted the body to consume sugar.

Xu Qi'an really needed sugar right now.

The postman brought them Guiyuan egg flower sweet soup, raisin pastries, almond tofu... all sweet.

Among the options, Xu Qi'an chose the Guiyuan egg flower sweet soup for himself and pushed the almond tofu towards Song Tingfeng, who had narrowed his eyes. Song Tingfeng immediately became happy and said with a smile, "Ning Yan, how did you know that I like to eat sweet tofu?"

Because you look like a heretic... Xu Qi'an laughed and said, "Because we are brothers. Seeing you in tears, I'll give you some tofu to sweeten your heart."

Who was in tears? Song Tingfeng rolled his eyes, knowing that Xu Qi'an was referring to Su Su's matter.

Speaking of which, Su Su was truly amazing. She was rare, a girl who could fight me for three hundred rounds... Song Tingfeng thought about the soul-stirring events that happened in the private room of the teahouse today. It was already the tenth hour.

"You wouldn't understand. You're a playboy, but I'm not." Song Tingfeng shook his head and sneered, "When you first joined the Nightwatchers, I advised you to marry Lv Qing, but you hesitated and ended up getting together with Fu Xiang. I knew then that you were the same type. If Lv Qing married you, it would be like a flower stuck in cow dung."

An image of Lv Qing's heroic and elegant appearance flashed through Xu Qi'an's mind, and he said irritably, "Although Lv Qing isn't as beautiful as Fu Xiang, it's too much to say she's cow dung."

"I didn't say she's cow dung, I said you are."

"Then what did you mean by a flower stuck in cow dung?"

"...."

After finishing the sweets, because the detective Xu Ningyan was not in good condition, Song Tingfeng took the initiative to take on the role of reasoning. He cleared his throat and said:

"Let's think from a different perspective. If I were Zhou Min, I would definitely hide the codebook in a place where the patrol team could find it at any time, but without attracting attention."

"Yes!" Xu Qi'an nodded.

"We have already checked Zhou Min's residence and found no secret compartments or suspicious things. We also compared the books he left behind just now." Zhu Guangxiao said.

Song Tingfeng thought for a moment and stroked his chin, "...maybe, it's not a book? Zhou Min is meticulous, and he can think of things that others can think of."

"Let's try a different approach. Could it be something that has words written on it, but is not a book? Ning Yan, do you think this is possible?"

"Very good, Tingfeng, your intelligence has successfully caught my attention. You are a genius who was delayed by the Official Brothel Sector." Xu Qi'an praised and asked, "So what do you think it could be? It's not a book, but it's among Zhou Min's belongings. And it has to be quite thick..."

Search tinyurl.com/2p9emv8w for the original.

Xu Qi'an suddenly stopped.

"Is it a calendar?!" Song Tingfeng was the first to shout.

The honest and hardworking Zhu Guangxiao accurately found a thick calendar among the belongings: "Is it this?"

"That's it!" Xu Qi'an exhaled the stagnant air in his chest and his eyes were filled with excitement.

It was a book, but not a book. It was eye-catching, yet ordinary. Based on the speculation and analysis of Zhou Min during this period of time, Xu Qi'an was extremely confident that this was Zhou Min's style.

The three of them eagerly opened the calendar and started counting from the first word, following the instructions to the one hundred and sixty-second word: "Day!"

The "day" of the Yi Mao day.

Then it was the three hundred and forty-seventh word, the fourth word, the first word, the second word.Combining them together: Mo Ri Guang Ding Yi Wu!

Obviously, this is wrong.

Then, they used the second method, taking the page numbers instead of the word count.

If we take the page numbers, then each word corresponds to a specific day on the calendar. The combination is as follows:

Mo, April 6th, January 15th, January 29th, January 25th, January 26th.

"No, that's wrong again." Xu Qi'an threw the almanac and cursed, "This line of thinking is incorrect, let's start over."

"Perhaps we can start by deciphering the word 'Mo' since it is the only word and it is at the beginning." Zhu Guangxiao proposed his idea.

The meaning of the first word is very important.

Xu Qi'an pinched his brow and asked, "Do you have any ideas?"

Zhu Guangxiao shook his head.

Xu Qi'an asked again, "Does the word 'Mo' have any special meaning in our yamen?"

Song Tingfeng pondered and said, "The Governor and Jiang Jinluo have already studied the secret codes. If the word 'Mo' points to a specific secret code in the yamen, Governor and Jiang Jinluo should be able to discover it."

"What can the Governor discover? He's only good at guessing riddles." Xu Qi'an shrugged, but in the next moment, he froze.

A flash of inspiration burst in his exhausted mind, like a spark of lightning.

He remembered when he was still in the police academy, a professor who studied criminal psychology once said that a person's behavior is closely related to their habits.

When analyzing and profiling a target, it is important to collect as much information as possible and understand their habits.

Even the most cunning criminal has a pattern of behavior, and that is their habit.

What is Zhou Min's habit?

It's word puzzles!

Yang Yingying said that Zhou Min likes to play word puzzles with her while drinking... So, when Zhou Min was thinking about how to hide evidence and leave clues, he would instinctively lean towards word puzzles... From this, it can be inferred that the only word in the two sets of secret codes is also a word puzzle. Xu Qi'an's train of thought became clearer and clearer.

Song Tingfeng and Zhu Guangxiao glanced at each other, maintaining a silent understanding. In that instant, Xu Ningyan's state returned, just like his wisdom and focus when he was investigating the Sang Bo case.

Mo, when separated, becomes 'black' and 'dog'... Xu Qi'an pinched his brow and asked, "I remember a colleague who went to Huangbo Street said that it's a dog market?"

Song Tingfeng nodded, "Yes, it's a dog market. What's the matter?"

Xu Qi'an said, "When 'Mo' is separated, it becomes 'black' and 'dog', and the information from Huangbo Street is a clue left by Zhou Min in the previous word puzzle game. I think it can be matched now."

"Do you think the secret code points to the dog market?" Song Tingfeng furrowed his brows, "But what does 'black' represent with just one word? Isn't it too arbitrary to conclude that the secret code points to the dog market?"

"I have an idea." Xu Qi'an didn't finish his sentence and called a postman.

"What can I do for you, gentlemen?" the postman asked.

"How much do you know about Huangbo Street?" Xu Qi'an asked.

"Huangbo Street, that place is chaotic. It's quiet during the day, but as soon as it gets dark, it becomes a mix of all sorts of people. There are thieves, wanderers, even bandits from the outskirts go to that street." the postman replied.

Whether they sell dog meat or other meat there... Xu Qi'an muttered to himself and said, "Bandits and wanderers wouldn't go there just to eat dog meat, right?"

"Of course not. Huangbo Street appears to sell dog meat on the surface, but it's actually a black market. They sell things that shouldn't be seen and engage in illicit transactions." the postman said.

"Have you been to the black market?" Xu Qi'an asked.

The postman immediately showed a guilty expression and stammered, "I went to buy dog meat."

Why act all embarrassed as if caught red-handed while pretending to be cool with your hands... Xu Qi'an furrowed his brows and said, "Speak in plain language."

The postman whispered, "I went to Xin 6th Store to find a prostitute. Buying dog meat refers to that."

Too young, even when looking for a prostitute, they act all shy and can't say it out loud... The three of them shook their heads and sighed at the same time.

"Xin 6th Store?" Xu Qi'an asked.

"The black market stores are named after the Heavenly Stems and Earthly Branches." The young postman blushed and felt like he was being publicly executed.

Xu Qi'an nodded, "I understand. You can go now."

As the postman closed the door and left, the sound of footsteps gradually faded away. Xu Qi'an shrugged, "The situation is already very clear. 'Black dog' refers to this black market that sells dog meat."

As for why there is such a place in the White Emperor City, engaging in illicit transactions under the nose of the government, it's not surprising.

Even in the city known for its philanthropy, there are many black markets.

Huangbo Street is not far from the post station, but it belongs to the outer city and there is no curfew at night."What does the other secret code mean?" Song Tingfeng asked himself and answered, "It should be telling us who to look for in the black market, or how to find them."

"The answer is in the almanac," Xu Qi'an said with certainty.

"We've already checked the almanac," Zhu Guangxiao looked at him.

"The idea of the almanac is correct, but how could Zhou Min leave such important clues in a relic?" Xu Qi'an said.

"It's an almanac from previous years, not this year's."

"Which year?" Zhu Guangxiao asked in a deep voice.

"Guangxiao, you're obviously not as quick-witted as Tingfeng today. There are so many almanacs from previous years. The Great Feng has been established for six hundred years, so it's like finding a needle in a haystack to find the correct almanac. Zhou Min doesn't seem that foolish. Since it's not this year's almanac, I guess that almanac has some kind of unusual significance to him."

"The almanac itself may not have any special meaning, but the year does, such as the year of birth, wedding day, etc. If I'm not mistaken, it should be the almanac from fourteen years ago."

"Because that was when Zhou Min was appointed to Yunzhou."

The old almanac from fourteen years ago was no longer at the post station, only the yamen and the bookstore still had it. In order to keep a low profile, Song Tingfeng did not go to the yamen, but went to the bookstore.

In the time it took to drink a cup of tea, he rode back with the old almanac.

Xu Qi'an found paper and pen, spread them on the table, and thought that his handwriting was not elegant enough, so he pushed Zhu Guangxiao to be the scribe.

They used the same method as before, using the "number of the word" to decrypt, but found that it was still incorrect, the copied words didn't match.

Then they used the "page number method", and on the 162nd page, it said May 12th, auspicious for opening a market, marriage, moving in, and traveling.

Inauspicious for praying for blessings, opening a warehouse, and digging a well.

"Opening a market!" Xu Qi'an caught the key information. "We should open a market at night and then go to the black market."

His statement was agreed upon by Song Tingfeng.

Next was the second set of secret codes: 3471242

Xu Qi'an flipped to page 347, and the date on this page was January 15th. He glanced at the almanac for that day and suddenly realized, the puzzle was solved.

"I understand!

"One hundred and sixty-two and three hundred and forty-seven refer to the page numbers, and four, one, two refer to the number of words. Tingfeng, look, what do the 4th, 1st, and 2nd words on this page spell?"

Song Tingfeng squinted his eyes and read, "Ding 15..."

Associating it with the information the postman had just said, he blurted out, "Black market shop, Ding 15th?"

The puzzle was finally solved...

Xu Qi'an and Song Tingfeng felt relieved, leaned back in their chairs, and let out a long breath.

Zhu Guangxiao also put down his pen, feeling relaxed all over.

Xu Qi'an walked to the table and took a closer look, with a surprised expression, he said, "Guangxiao, your handwriting is so ugly."

Song Tingfeng ran over to join in the fun and exclaimed, "It's unbearable to look at, unbearable..."

Zhu Guangxiao was not convinced, "Is your handwriting any better?"

Song Tingfeng proudly said, "My calligraphy is not inferior to that of scholars. When I was young, I saved money to buy paper and ink just to practice writing."

Xu Qi'an said, "My family was poor when I was young. To practice writing, I used a brush dipped in water to practice in the courtyard. I practiced for twenty years."

Zhu Guangxiao suspiciously glanced at them and handed the pen over, "Then show me your writing."

Xu Qi'an and Song Tingfeng turned around tacitly, shoulder to shoulder:

"Let's go, rest in our rooms. Calligraphy is not for showing off."

"I think so too."

Watching the two of them leave, Zhu Guangxiao opened his mouth and looked down at his own handwriting, secretly deciding to start practicing calligraphy in the future. He couldn't fall behind them in this small team.

Back in his room, Xu Qi'an took off his shoes, sat on the bed, and meditated to ensure that he would be in good condition when he went to the black market at night.

Perhaps his brain was too exhausted, he hadn't entered a state for a long time, his thoughts were uncontrollably scattered and difficult to gather.

...Calculating the time, Huai Qing and Lin An should have received my letter by now... I hope that letter can turn Huai Qing's anger into joy, although I don't know where I offended her... Biao Biao, that silly girl must be very touched, she's even better at flirting than Chu Caiwei, that glutton who hasn't experienced love yet...

As for whether the two princesses would communicate privately through letters, or if someone outside of them would see them, Xu Qi'an thought it was impossible.

First, Huai Qing and Lin An have a bad relationship, so there is no possibility of exchanging letters. Moreover, the letters he wrote were somewhat ambiguous, and girls in this era have their pride, so it's impossible for them to tell others about such letters.Secondly, both Huai Qing and Biaobiao are mature princesses, mature enough to conceive, and have the freedom and power to send and receive letters. The emperor and the concubines would not interfere, and others would not dare to privately open the princesses' letters.

The possibility of him, a small gong, writing ambiguous letters to the two princesses and being exposed was almost non-existent.

Gradually, Xu Qi'an entered a contemplative state.