I'm curious about how Anime are distributed in Japan. Are they held by various networks? Or do they all go to the NHK? etc.
Well in general anime is usually distributed through, including Japan,
- Videogram (DVD, Blu-ray)
- TV (Technically it's Broadcasting)
- Screening on Theaters for Movies
- Internet i.e Streaming
Now if you are asking whether NHK is the only corporation that broadcasts anime, then the answer is No. In many cases, the said anime series is broadcast only in the area of the station producing the anime, which is usually Tokyo. In other cases it can be Osaka and Nagoya. And UHF anime tends to be broadcast in Osaka, Nagoya, and Kantō region, but not in Tokyo.
There are seven nationwide television networks (Terrestrial television) in Japan. Two owned by the national public broadcaster NHK and the remaining five belonging to the commercial sector. The Seven networks are the following,
- NHK General TV
- NHK Educational TV
- Nippon News Network (NNN)
- All-Nippon News Network (ANN)
- Japan News Network (JNN)
- TX Network (TXN)
- Fuji News Network (FNN)
As you can see from the links below all the networks (Terrestrial television) broadcast or broadcasted anime,
- NHK Broadcasted/Distributed Anime List
- NNN or Nippon TV Broadcasted/Distributed Anime List
- ANN or TV Asahi Broadcasted/Distributed Anime List
- JNN or TBS TV Broadcasted/Distributed Anime List
- TXN or TV Tokyo Broadcasted/Distributed Anime List
- FNN or Fuji TV Broadcasted/Distributed Anime List
In addition to Terrestrial there are also Satellite, Cable, and UHF broadcasting.
Some Satellite television examples,
- Wowow (and Anime Complex)
- SKY PerfecTV!
Some Independent UHF Stations (aka "UHF anime"),
- TV Kanagawa
- TOKYO MX
- TV Saitama
- Chiba TV