My First Time City Planning

[Tier-Group 3 Rooftop Observation Deck]

"To the west, between us and Iruma, there's a stretch of lowland that runs off toward the south. But as far north and east as I can see, it's wasteland, plateau and lowland tangled together. That mountain on the eastern horizon is Tsukuba, most likely."

Marie explained, holding her own crude, hand-drawn map up against the actual terrain.

"This hill seems to have always served travelers as a landmark, and five roads converge on it. West to Iruma, east to Ibaraki, northeast to Nasu-Shiobara, and running across the plateau from northwest to southeast, the run-down Nakayama Highway that links the Land of Ke and the Land of Sō. None of them, mind you, are proper highways with the post-stations laid out the way they ought to be."

In the otherworld's Tochigi Prefecture it's Nasu-Shiobara. This world's salt-flat plain is written differently and read "Nasuengen."

"It'd feel more balanced if there were a road on the southwest side too…"

"True, that would give us six directions at nearly equal spacing, but there's nothing to the southwest. If the lowland up ahead were sea, we could at least build a harbor."

"Um, Marie-san, the 'Six Realms of reincarnation' you mentioned, that's six races, right? So we could match the six directions to the six races, and make the one direction that has no road into a 'Hell Gate' and put the execution grounds there."

"A Preta Gate would do just as well, surely. This dungeon already has more than enough Asura; we've no need of Pretas. The west, toward Iruma, has plenty of humans, so a Human Gate, ah, and look, 'Iruma' and 'human' even look alike as words. Then we slap the rest on however, northwest the Beast Gate, northeast the Asura Gate, east the Heavenly Gate, southeast the Hell Gate, something like that. Although, since the twelve zodiac signs and the eight trigrams are tied to the compass directions, we ought to check properly whether the Six Realms have any relation to direction before we decide."

"Tabled, I suppose."

"Asura such as myself absolutely loathe being made fools of by others, and adore looking down on others, so I would very much like to rule out the possibility of committing some blatant blunder."

One must never give an Asura the Internet. Catastrophe is a foregone conclusion. Even Marie, behind a screen of anonymity, there's no telling what she might get up to.

"As for the five highways, let's make them dead straight, so we'll be fine even once we can mass-produce automobiles someday. In point of fact, the Roman roads were straight too. As for width… that's the hard part. A hundred-meter road is one rule of thumb, but even that won't be enough once the population swells to several hundred thousand."

"You really think we'll need that much?"

"Japanese cities, by historical accident, have high population density and narrow roads, and they make up for it with railways. In Tokyo City, for instance, eighty percent of traffic volume rides the rails, but if we were to carry all of that by automobile instead, we'd need at least ten times the road, especially the roads linking the city center to the suburbs. This dungeon hasn't so much as a horse-cart yet, but since we have the luxury of a planned city with no constraints on land, I'll secure ample ground against the distant future."

Tokyo City's population density is sixteen thousand persons per square kilometer, fully twenty times that of Los Angeles County, which despite a comparable population of just over ten million sits at eight hundred persons per square kilometer.

"True, with dungeon structures an elevated road would be easy enough, and if a hundred meters won't do, we can just stack them like the Bijogi Junction."

"That said, for the time being everyone goes on foot, so even if we improve the highways, a day's travel will be thirty to forty kilometers, same as the Edo period. Ten kilometers or so between post-stations is the standard. Though around Saitama in the Edo period there were rather more stations than that."

"Even if we lay out highways and post-stations, it's a problem if pirates come raiding."

"That's exactly it. We'd have to go so far as to station five knight orders along the five highways. Right now we have only the one knight order, so first the road to Iruma, the nearest, on a map of Saitama Prefecture that would correspond to the Kawagoe New Road, I suppose, that's what we'll improve."

"So we extend the road in step with the expansion of the dungeon's sphere of influence."

"We level the ground with the dungeon function and designate the surface as dungeon structure, and it's done. We've used up our dungeon energy, and we don't need a twenty-lane road just now, so for a start we'll keep the paving to about five meters wide."

"I wonder if dungeon structures need maintenance or anything like that."

"They're maintained by dungeon energy, so no maintenance is required. Which means overbuilding will become a burden eventually, but with a tower-type dungeon this tall, the energy coming up from the Core is quite considerable, so as long as we don't squander it we'll be fine."

"And so, we'll improve the highway west to Iruma first. We'll fold the route into the dungeon's sphere of influence stretch by stretch up to the outskirts of Iruma, lay down dungeon-structure paved road, and develop the post-stations. By the Nara-period reckoning, post stations every sixteen kilometers; by the Edo-period reckoning, every ten. Which shall it be?"

"This world uses the shakkanhō measures, so the metric system won't be familiar to them."

"Then shall we place stations at intervals of two to three ri, like the Edo period, and accommodate not just the strong-legged who can do ten ri a day but also those who can't? It's about seventeen ri to Iruma, so for a start I'll put a lodging around the eighth or ninth ri and make it a two-day journey, I think."

"That sort of thing, you can just figure out once you've folded that far into the dungeon's sphere of influence, can't you?"