Inubashiri MomijiFrom the Momiji-related section of Symposium of Post-mysticism, "New pieces discovered [by Momiji] in Muenzuka / the discovery of shogi pieces never before seen among the kappa has become a hot topic." (Bunbunmaru News)
Waterwheel, forests, a shogi-playing white wolf tengu and a following wolf, represent Gensokyo's serene life. But from "newly discovered pieces include the 'general', 'lieutenant general', and others which appeared to be promoted versions of pawns; and also other pieces like 'airplane' and 'spy', whose effects are truly unimaginable", the outside world is most likely in the midst of a war. The background consists of fighters representing the situation in the outside world. Since civilizational progress outside led to war, perhaps it's better for Gensokyo to stay as-is.