The blueprints for Xiaoyao Tower were finally finalized after Du Heng and Princess Changle repeatedly pored over them. They revised it through seven drafts in total, and the two of them stayed up for three straight all-nighters; even the most experienced old craftsmen from the palace’s Bureau of Imperial Manufactories could not help but sigh, “How is this an ordinary set of architectural drawings? This is clearly a fine method for governing the affairs of the world!”
The chief master craftsman of the Ministry of Works’ Directorate of Craftsmen… Lu Ke, a descendant of the Lu line who was over sixty years old… held the blueprints and examined them carefully again and again, and the more he looked, the more astonished he became, to the point that his hands could not help trembling slightly. “This building… is truly something never seen before! It is not an ordinary restaurant at all, but a tool for spreading gewu art!”
One had to know that traditional restaurants were mostly two-story wooden structures with carved beams and painted rafters, putting all their thought into decoration while neglecting practicality. Some restaurants even deliberately designed narrow staircases, hidden stove areas, and secret rooms to look luxurious, and as a result they became places that harbored filth and corruption. But the Xiaoyao Tower that Du Heng designed was steeped in the thinking of gewu everywhere… everything was people-first, guided by principles, and practicality came first, with not a shred of empty showmanship.
1st floor · Public Hall: A down-to-earth “commoners’ dining hall.”
It was furnished entirely with Eight Immortals tables, paired with chairs that had backrests. The chair backs were deliberately made at a slight incline, so you would not feel tired even after sitting for a long time, and the table corners were all polished round to prevent children from bumping into them while running around.
The green bricks on the floor were also laid with care, with the whole surface slanting three degrees to one side. On rainy days, standing water could flow along the slope into an underground covered drain, so it would neither be slippery nor flood with puddles, and walking on it felt steady and secure.
High windows and low lattice vents were opened in the walls, with the high windows above drawing in fresh breeze and the low vents below expelling stale air. The oily smoke from the stove was vented directly through ceramic pipes into the chimney on the roof, so the entire hall did not fill with choking fumes, and the air stayed clean and refreshing while people ate.
At the entrance stood an “Ingredient Traceability Board,” updated daily with new content. Today’s pork came from Butcher Zhang of Lantian (with Butcher Zhang’s seal attached to reassure people), the greens were freshly picked from the East Garden of Dujiawa (even the picking shichen was written clearly), and the soy sauce was fermented for seven days (with the jar number marked so the specific batch could be traced). Anyone could understand where the food on the table came from, and they could eat with peace of mind.
2nd floor · Private Rooms: A tasteful “gewu classroom.”
There were six private rooms in total, each named after the “Six Arts of gewu”: Agriculture Room, Crafts Room, Medicine Room, Mathematics Room, Chemistry Room, and Mechanics Room… the names alone carried an air of learning.
Each private room was fitted with a pulley serving hatch, and food boxes could be hoisted directly from the 1st-floor kitchen through pulleys, so the waiters did not need to run up and down. This both ensured guests’ privacy and quiet and saved manpower.
What hung on the walls were not ordinary calligraphy or paintings, but gewu diagrams. The Agriculture Room depicted crop rotation methods and composting steps, the Crafts Room displayed the principles of levers and pulleys, the Medicine Room posted a sketch of “mold curing epidemics” (with a special note: penicillin extract can inhibit ulcer toxins), the Mathematics Room hung excerpts from The Nine Chapters on the Mathematical Art, the Chemistry Room listed a glass formula, and the Mechanics Room displayed models of steam devices. People could learn knowledge while dining, achieving two things at once.
Back kitchen · Transparent Kitchen: A reassuring stove that dared to “show itself.”
It had a fully open design, with only bamboo curtains used as a slight partition, so diners could see the entire process of the chefs stir-frying through the bamboo curtains. The iron wok flipped in their hands, the heat was controlled with precision, and the finished dishes looked glossy with oil yet not greasy, which put people at ease.
There were ten iron woks in total, and the stove area was divided by function. The raw stove handled raw ingredients, the cooked stove was responsible for stir-frying, the sauce stove was used for simmering sauce ingredients, and the soup stove was dedicated to stewing soup, with raw and cooked strictly separated to eliminate cross-contamination at the source.
In the corner there was even a “Suggestion Handling Desk,” where Du Heng personally sat every day. If diners had any suggestions, they could raise them on the spot, and reasonable suggestions were improved that very day, with the results of the improvements publicly posted so everyone could see.
A detail-obsessed “ultimate pursuit”: Even rags had rules.
Du Heng’s standards for details practically reached the point of being “nitpicky,” but every single part was thoughtful.
The service bell was made of copper, with a reed embedded inside, so the sound was crisp but not harsh. A single shake could be heard, and it would not disturb other guests.
The menu was printed with colored ink, with meat dishes marked in red and vegetarian dishes marked in green. Next to spicy dishes there was a small flame drawn, and next to mild ones there was a small water droplet drawn, making it both illustrated and textual, so even elderly people who could not read could order by looking at the pictures.
The ends of the chopsticks were engraved with numbers, with each table having its own set, to prevent mixing that could cause illness.
Even the latrine was separated into men’s and women’s, and it was fitted with a flushing clay jar. Rainwater from the eaves was guided into the jar, and stepping on the mechanism would flush it, making it clean and odorless, far better than the latrines of most restaurants at the time.
“Young lord Du, if this building gets built, the other taverns in Chang’an City should be ashamed enough to close down!” Lu Ke stroked the blueprints and sighed from the bottom of his heart, “This old man has built buildings for forty years, and only today did I learn that a building can carry principles and spread learning.”
Du Heng just smiled and shook his head, and he said calmly, “I am not trying to make other restaurants feel ashamed, but to set a standard. If our peers can follow and imitate it so that commoners can all enjoy this kind of service and experience, would that not be even better? The key to gewu lies in sharing knowledge and technology, not monopolizing it.”
After hearing this, Princess Changle strongly agreed, and she immediately ordered the Bureau of Imperial Manufactories to specially produce “Xiaoyao Tower dedicated utensils,” requiring them to be uniform, clean, and traceable to their source.
The bottoms of the celadon bowls were stamped with the Xiaoyao seal script, so that if a bowl broke, the production batch could be traced through the mark.
The chopstick holders were engraved with “One dish, one style; 100 dishes, 100 flavors,” reminding everyone to savor the taste of each dish carefully and not to gorge themselves.
Even the rags were divided by color: red for wiping tables, blue for washing dishes, and white for wiping mirrors, to avoid cross-contamination.
Even the trays had copper edging embedded to prevent bumps and breakage and extend their service life.
On the day Xiaoyao Tower began construction, even Emperor Taizong of Tang Li Shimin personally came to the site.
Before dawn, the construction site was already churning with yellow dust, and more than one hundred craftsmen stood in neat formation. Li Shimin wore dark-black armor and had not yet shed the dust of campaigning; he stood before the foundation with his hands clasped behind his back, his gaze sharp as a torch. He watched Du Heng direct the craftsmen to raise pillars, lay pipelines, and build the stove, and every step was orderly and clear, with crisp commands and none of the awkwardness of ordinary craftsmen. Instead, he had a bit of a commander’s bearing… dispatching craftsmen like commanding troops, dividing labor like deploying formations, and even stacking timber in perfect order according to the sequence of use for easy access.
“This Du Heng can become a Vice Minister of the Ministry of Works in the future.” Li Shimin said this to Zhangsun Wuji beside him, with a tone full of praise.
Zhangsun Wuji’s face was dark, and his hand inside his sleeve clenched tightly as he only replied coldly, “I fear he is too young and too impatient, and it will be hard for him to convince everyone. Moreover, he has no imperial examination degree, and if he suddenly rises to a high position, I fear it will disrupt the court’s discipline and order.”
Li Shimin did not refute him, and he only had an attendant grant Du Heng a golden abacus. On the abacus were carved eight characters: “Plan carefully, benefit the nation and the people.”
Du Heng knelt to thank him, but he did not carry the golden abacus on his person, and instead hung it on the lintel of the construction site’s accounting office. He himself still used wooden counting rods to keep accounts and used bamboo slips to record detailed income and expenditure.
“A golden abacus is Your Majesty’s grace, and it is enough to display it. Wooden counting rods and bamboo slips may be plain, but they can truly keep accounts.” He smiled as he explained to Princess Changle, “I must let the craftsmen know that Xiaoyao Tower values what is practical and does not pursue empty vanity. Only when the accounts are calculated clearly can everyone feel at ease, and only when everyone feels at ease can this building be built solidly.”
In the dead of night, Du Heng sat alone by the bonfire at the construction site and drew the final illustration… the night-view drawing of Xiaoyao Tower.
In the drawing, the lanterns used self-produced glass as lampshades, and the light spilled through the glass, soft and not glaring, illuminating the “Xiaoyao” plaque like a bright moon hanging on the building.
Copper wind chimes hung from the eaves corners, shaped like ancient qing chimes, and when the wind blew, they made a crisp sound, with a pleasant tone that could give people sweet dreams.
Before the building’s entrance there was set a “Membership Stored-Value Board,” where depositing 100 copper coin in advance would gift 10 copper coin. The wooden plaque was carved with the guest’s name, and it could be transferred to others or refunded in cash.
At the wall corner’s gewu corner, he also designed a night-time display area. Fluorite powder was painted onto the levers models, so they could emit a faint glow at night, and children could touch them and learn the principles of levers even under moonlight.
Du Heng knew clearly in his heart that this Xiaoyao Tower was not just a restaurant, but a physical embodiment of the gewu philosophy, a testing ground for business models, and a funding source for research into advanced technology. Every single coin earned from here would become the bricks and tiles of the Gezhi Institute, the firewood for the glazed kiln, and the herbs of the medicine workshop, supporting gewu art as it continued to develop.
Three months later, when Xiaoyao Tower rose from the ground and the rational glow shone through its flying eaves and bracket sets, the commoners of Chang’an would understand…
A prosperous age was not only written in memorials to the court, but was also hidden in the worldly smoke and fire of a fragrant bowl of shepherd’s purse stir-fried cured meat.
And that pair of couplets, already drafted long ago, would eventually be posted in every corner of Great Tang.
Upper line: One dish, one style, gewu zhizhi.
Lower line: One hundred dishes, one hundred flavors, flavors connecting to all the people.
Horizontal inscription: Xiaoyao Under Heaven.
Du Heng stood atop the still-unfinished rooftop and looked toward Qujiang. The autumn wind lightly brushed his cheeks, and he seemed to see that little peach tree by the Qujiang bank had already bloomed with new flowers. Princess Changle stood beneath the flowering tree, holding a glass cup, smiling as she asked him, “Are you willing to share this cup of wine with me?”
He answered softly, “I am willing to spend the rest of my life guarding this stove’s smoke and fire for you, and also to trade it for the cooking smoke of ten thousand households for the common people under heaven.”
The stove fire was about to be lit, and the great path of gewu was about to be laid.
This Xiaoyao Tower was never just a building.
It was the starting point of a new era.