42.195 km (Day 7)

[Core Room]

"Marie-san, just how many more days are we to spend idly crushing zombies like this, with no plan to speak of?"

"Taipei City has just finished. Next will be the satellite cities, Banqiao and Sanchong and the rest. Once we've summoned the libraries of Taiwan, there are no more large libraries left in the South Seas Islands, so we'll summon four from Karafuto at the very end, and the first stage will be more or less wrapped up.

After that, as the second stage, we'll summon the single-story and two-story libraries one after another, building up steadily, five meters or ten meters per building, five from Karafuto, sixty-eight from Hokkaido, thirty-one from Aomori, from Iwate…"

"Haven't you summoned something like a thousand buildings already?"

"The tier-group count is 1,542. The Imperial Library is treated as Tier-Group Zero, so the number of tier-groups comes to 1,543. Which means, er, well, we've added 989 buildings so far, and the height has passed 42 kilometers. The remaining additions planned for the first stage come to 103 buildings, which should bring the height to 44.5 kilometers."

Sleep-deprived, Marie's powers of calculation were duller than usual.

"That's a height you could run a marathon on."

"We could hold a vertical marathon, perhaps."

"A vertical marathon with an elevation gain of 42.195 kilometers, that's madness on the order of climbing Niitakayama ten times over."

"In the Korean Empire there are said to be people who have climbed Mount Kongō more than ten thousand times."

By the way, the reason a "Kongō-class battlecruiser" exists in an otherworld where the annexation of Korea never happened is that the name derives from a Mount Kongō somewhere, in Sado or Nara or wherever.

"A vertical marathon might not be a bad idea. Say, the first to run all the way to Tier-Group 2 (directly below Tier-Group 3, the second from the top) enters my service. Something like that."

"You may well end up with someone who overreaches and meets the same end as in Tolstoy's 'How Much Land Does a Man Need?', though. It is, after all, a height that takes forty minutes by an ordinary transfer circle."

"Does it really take that much?"

"A transfer circle is, in truth, a linear-motor elevator, and it normally runs at sixty kilometers per hour. Both acceleration and deceleration are at most 0.9 meters per second squared, with a rate of change of 1.3 meters per second cubed. These are said to be values one finds comfortable even riding standing up. The high-speed transfer circles we have now use the same acceleration and deceleration, but they manage five thousand meters per minute, that is, three hundred kilometers per hour. The travel time comes to about ten minutes. By specification we could push them a little faster."

Since the acceleration is vertical, only one's apparent weight changes; were the same acceleration applied horizontally, it would knock a person off their feet. There is nothing like it in the otherworld Marie and the others know, but for reference, the bullet train accelerates at 1.7 km/h/s, that is, 0.47 meters per second squared, half that of a transfer circle.

"And the zombie dungeon's situation is the same as ever?"

"It is. We keep up the provocation around the clock, rotating shifts as needed. Here we go by variable-length hours, so we don't actually say 'around the clock,' but…"

"So in the end the water couldn't dig away the enemy dungeon."

"No. But since we've washed away everything but the dungeon itself, we can make out the zombie dungeon's shape quite well. It's about 150 meters north to south and 60 meters east to west. It runs a little longer north-to-south than the otherworld records had led us to expect. Most likely the graveyard on the north side of the execution ground is included as well."

"It couldn't be that its dungeon energy is unlimited, could it?"

"True, as the saying goes, 'Though the grains of sand on the beach run dry, the seed of thieves in this world shall never run out.' But if it were inexhaustible, we'd soon run out of libraries we can summon ourselves."

"If it really were inexhaustible, couldn't it summon even high-cost things, an imperial university library, or a foreign national library?"

"Shall we set our sights on the Library of Congress, then? It's several times the scale of the Imperial Library, so the dungeon energy it'd take would likely be several hundred times as much, or several thousand."

"If that's the policy we've settled on, then wouldn't it be better to rest until the energy builds up?"

"Let's do that. When I wake, I'll stack up the rest of the libraries of Taiwan and the like as I see fit. For the second stage I suppose I'll just register them to the Core, then hold off and let the energy accumulate."