It is possible that "王国之心" (Kingdoms Heart) is not available on Steam. Steam is a digital distribution platform for video games, and it only includes games that have been authorized by the platform and the game developers or publishers. If you are unable to find a particular game on Steam, it may be because the game is not available on the platform, or it may be because the game is not yet released or has been removed from the platform.

1. If you are looking for a specific game and are unable to find it on Steam, you may want to try searching for it on other platforms or websites that offer video games for purchase or download. It is also possible that the game may be available for purchase or download through the developer or publisher's website or through other online marketplaces.

Alternatively, if you are looking for "王国之心" specifically, you may want to check with the game developer or publisher to see if the game is available for purchase or download through other channels.