The Floating Citadel of Doraemon

Li Gu Du, Yan Jin County

As one of the pivotal ferry crossings of the Yellow River north of Bianliang, Li Gu Du had, since the twilight years of the Tang Dynasty and the tumultuous Five Dynasties period, become a fiercely contested strategic point in the north-south campaigns of warlords. The surging Yellow River flows past the town to the north, making it an unavoidable passage for Song envoys journeying northward from the capital. Within the town, compacted earthen roads intersect in a crisscross pattern, forming a grid-like layout. Rows upon rows of dwellings stretch for miles, numbering in the thousands. Inns and hostels abound—more than a hundred in total—serving a constant stream of merchants, travelers, and wanderers from all corners of the realm. The principal residences are uniformly constructed with large tiled roofs, lofty and spacious, surpassing the humble abodes of common folk in other regions, a testament to the wealth and prosperity of the townspeople.

Yet this once-flourishing market town, enriched by commerce and traffic, now shares the same grim fate as countless villages across Hebei and the Central Plains—laid waste by the savage Jurchens. Amidst broken walls and crumbling ruins lie charred and blackened corpses, the air thick with the pungent stench of decay that refuses to dissipate. The vast ruins are cloaked in utter silence; not even the cry of a rooster or the bark of a dog can be heard. Though over two months have passed, the entire town remains frozen in the moment of its slaughter.

Gazing at the desolation—ruined homes and decomposing bodies—everyone felt the brutal weight of war press upon them. Helpless, they turned back and set camp in the wilderness beyond the town. To Wang Qiu's mild astonishment, Nobita Nobi, despite being but a schoolboy, did not succumb to vomiting or faint in the presence of such grotesque and mangled corpses. Though his face paled and his steps faltered, he displayed remarkable psychological resilience. Then again, considering how many times Nobita and his companions had saved worlds and vanquished monstrous foes, Wang Qiu found this fortitude rather understandable.

By now, the skies had cleared. Rare winter sunlight spilled through rifts in the leaden clouds, cascading upon the earth, though it offered little warmth to the shivering travelers. A few officers sought refuge from the wind beside fires, warming themselves. The soldiers, however, remained occupied. Dozens of mounts were led to the roadside, their saddles loosened as they bowed their heads to nibble on dry grass and feed cakes of bean mash and wheat bran the soldiers had foraged or carried.

Other soldiers retrieved paper-wrapped rations from saddle pouches—standard-issue military provisions of the Song army. These compressed rice cakes were made from cooked and sun-dried glutinous rice, then ground and shaped. Paired with a small packet of salted fermented black beans—so salty they were nearly indistinguishable from blocks of salt—these cakes served as a typical meal for a Song soldier. Such rice cakes, known in antiquity as qiu, date back as far as the Northern and Southern Dynasties, with references in Essential Techniques for the Common People, and even made their way to Japan, where they became a staple for travelers during the Heian period.

As with all military rations, the taste left much to be desired—dry, coarse, and hard to swallow. When circumstances allowed, army cooks would boil them into gruel, adding wild herbs or pickled vegetables before ladling the mixture out for the troops. At this moment, several soldiers were doing just that, tossing rice cakes, salted beans, and water into small iron pots suspended over campfires, occasionally cutting strips of vinegar-soaked cloth and stirring them in.

—Apart from these portable rations, the Song army's logistics corps also employed a vinegar-soaking technique using coarse cloth. After soaking in vinegar and drying, the cloth could be carried easily. When needed, a small strip could be cut and added to boiling water to create a tart, invigorating broth.

This level of logistical foresight reveals that the Song military's supply chains were strikingly advanced for their time, approaching modern sophistication.

Yet, tragically, such a force—well-equipped, amply supplied, generously salaried, and surpassing its age in both organization and military theory—was still repeatedly bested by marauders who relied on plunder for supplies and primal instinct for tactics.

Of course, for all their supposed sophistication, these ancient portable rations were still seen as coarse sustenance, fit only for the rough-hewn soldiery. For a pampered scholar-official like Qin Hui, the Imperial Censor and overseeing field commissioner, such food was beneath notice—even on campaign. Beside a roaring fire, his servants had already laid out a felt mat upon which rested trays of sculpted candied fruits and glutinous rice confections, along with freshly warmed sesame flatbreads. A raw chicken, blue with cold, had been marinated and skewered on a spit, roasting over the flames with an enticing aroma.

Seeing that the chicken would take time to cook, Qin Hui first nibbled on a meat-stuffed flatbread with preserved fruit to stave off his hunger. A pot of heated lamb wine was quickly brought forth. Lifting the ewer, he poured himself a cup and sipped, smacking his lips in satisfaction—the authentic lamb wine was milky white, brisk and mellow, with a potent aftertaste, perfect for dispelling winter's chill. Only the seventy-two official establishments of Kaifeng could offer such a vintage, and Qin Hui had wisely stocked up upon learning of his appointment.

As he drank his third or fourth cup, warmth slowly rising from his throat, he saw Master Guo Jing—the Taoist sage—descending from the river embankment ahead, arms folded and his face filled with displeasure. At once, Qin Hui abandoned his wine and delicacies, rose to his feet by the fire, and bowed in greeting. He inquired after the condition of the road ahead and whether the journey north could continue.

"...As expected, it's a tough situation," Guo Jing sighed. "The Yellow River ahead has sunk into a ravine—it would take a monkey to climb across!"

…

The sudden desiccation of the Yellow River near Li Gu Du, ironically, was the result of Doraemon and the other time travelers' own doing.

Earlier, Doraemon had used his Weather Controller to cause an unnatural surge in temperature—from a bitter minus eighteen degrees Celsius to over forty degrees—in the heart of winter in Tokyo-Bianliang. The result was a rapid thawing of the previously frozen Yellow River.

However, though the lower reaches melted, the upper river remained locked in ice. Worse still, due to centuries of silt buildup, the Yellow River had become a "suspended river," raised above the surrounding land. Side streams could not replenish it, and it depended solely on upstream flow. During the dry season, water levels were already perilously low. So when the thawed waters downstream drained away, there was nothing from upstream to sustain the flow. As a result, the riverbed from Zhongmu County downwards fell dry.

Meanwhile, further downstream, an unusual winter flood broke out, turning the region into a snowy, frozen marsh. The waters, blocked by still-frozen river mouths near the sea, had nowhere to go but over the ice—causing massive overflow.

Of course, such a minor calamity paled in comparison to the atrocities of the Jurchen invasion.

Back to the present, with the riverbed at Li Gu Du now dry and both upstream and downstream once again frozen, it became a treacherous ditch of frozen mud. Guo Jing's "Mini Northern Expedition Force" had no choice but to climb down the steep embankment, tread carefully through the uncertain mud—some of which might not be fully frozen—and then scale the opposite bank, a task akin to mountaineering. For agile scouts or elite troops, this might be feasible, but leading horses and supply carts would be another matter entirely.

Thus, it had been Zong Ze's recommendation that they detour upstream by over a hundred li to find solid ice and cross safely.

However, for Doraemon—with his infinite gadgetry—such logistical woes were mere trifles.

"…No problem at all! If we can't walk across the ground, we'll simply fly over it! Besides, I'm tired of walking," Doraemon declared nonchalantly.

Nobita nodded in fervent agreement—despite having help from the Universal Reins and Momotaro's Taming Dumplings, two days of horseback riding had left the city boy, long accustomed to using Anywhere Doors, sore and hobbling. He had been grumbling for some time.

"…Fly across? That's not a bad idea! But do you still have any spare Bamboo-Copters? And these Song folks might not even know how to use them!" Wang Qiu voiced his approval but also his concerns. He remembered that Doraemon had accidentally lost his last spare copter during a harrowing adventure in the Resident Evil world's Hive Base and had yet to restock.

"…I'm not talking about something so petty as a Bamboo-Copter! This time, we're going big!" Doraemon replied with a triumphant grin, producing a set of gadgets for creating the Cloud Kingdom: the Condensed Cloud Spray and the Fully Automated Universal Construction Machine.

"…Let's do something grand—let's build a flying fortress of war!"