Why did Japan get several official guides for the same game?
Start with the counts, because the counts are the argument. For Twilight Princess in 2007, Japan received four separate licensed guides from four different houses: the Shogakukan official guidebook, the Enterbrain Perfect Guide (256 pages, ISBN 978-4-7577-3390-9), the Nintendo DREAM guide, and the Kadokawa Complete Guide, the biggest of the four at 350 pages. The Library documents each of them on its own page on the Zelda shelf. One game, four official books, all in the same season, none of them a reprint of another.
The pattern repeats
Castlevania tells the same storyFor Symphony of the Night, Japan had three separate official guides from NTT Publishing, Futabasha, and Shinkigensha, and the pattern repeated for Castlevania 64. America had one licensed guide, the BradyGames book, plus a Prima book that printed the word unauthorized in its own title. The Library's Castlevania guide page documents that split in full. In Japan, rival publishers competed inside the license. In America, the competition had to stand outside it and say so on the cover.
The American model, in a guide writer's words
One official book, by contractDoug Walsh, who spent 18 years writing guides for BradyGames and Prima, explained the American arrangement to Kotaku in 2019: guide publishers paid the game publisher a hefty combination of licensing fees and royalties in exchange for the rights to be the only official guidebook for the game, and the licensor reviewed the book before print. One licensee per game is a deliberate structure, not an accident. It makes the official guide a monopoly product for that title, which is why the American shelf for a big game usually holds exactly one official book and, at most, unauthorized rivals beside it.
The deeper bench
American writers worked from Japanese guidesThe Japanese bench was not just wider, it was earlier and deeper, and American guide writers relied on it. Walsh describes transcribing skills, equipment, and level data from the Japanese guide for the PSP remake of Tactics Ogre, on Square Enix's own recommendation, matching kanji against a master vocabulary file for weeks. For Tales of Vesperia in 2008, his team had the opposite problem: the game launched the same month in Japan, so there was no Japanese guide to work from yet, and he records that they missed secret side quests as a result. A publishing culture that produces several thorough guides per game had become, in effect, reference infrastructure for the culture that produced one.
An honest limit
What the record does not carryNo Japanese publisher policy document explaining the multi license model was found in the sources opened for this page, so the Library does not invent a stated reason. What is documented is the output itself, title by title and publisher by publisher on the Zelda and Castlevania shelves, and the American single license model in the words of a writer who worked under it. The shapes of the two shelves are the evidence.