“A Single Samurai” was first published in The Baen Big Book of Monsters published by Baen Books.
In this story a mountain-sized kaiju has arisen in Japan, rising from beneath the land itself where the landscape had built up around it. The monster is moving across the countryside, crushing everything in its path. A samurai has survived its uprising where so many others haven’t by riding the kaiju as it rose up and climbing up its back even as the soil and trees and rocks shift off the kaiju as it walks. To save Japan he has to finish his climb and find some way to kill the monster.