Just a quick correction. Mojang hasn't hired the guy that created Forge. They hired Dinnerbone and grum, two guys from Bukkit (a server plugin API). They also hired developers from MCP (Searge and Professor Mobius), which enables Forge to do what it does.
Forge's early contributors have mostly moved on from the modding scene, but the current maintainers are cpw and LexManos. They've worked with Mojang on a few issues, such as the block model format, but haven't been hired by them.
Additionally, I'm not sure if you meant it this way, but the mods you mentioned aren't by Japanese developers. There is a significant modding scene in Japan, but there's little overlap with the more common mods such as you listed above. Some notable mods from that community are StarMiner[1], RealTrainMod[2], and Helicopter Mod[3].
By "modding API" in my first edit I was actually referring to MCP. I couldn't think of a better description.
The mods I mentioned aren't indeed by Japanese developers but I can now see how my wording is wrong. I meant to say that the Japanese modding community is also active and doing wonders. Thank you.
Forge's early contributors have mostly moved on from the modding scene, but the current maintainers are cpw and LexManos. They've worked with Mojang on a few issues, such as the block model format, but haven't been hired by them.
Additionally, I'm not sure if you meant it this way, but the mods you mentioned aren't by Japanese developers. There is a significant modding scene in Japan, but there's little overlap with the more common mods such as you listed above. Some notable mods from that community are StarMiner[1], RealTrainMod[2], and Helicopter Mod[3].
[1] http://forum.minecraftuser.jp/viewtopic.php?t=17975
[2] https://www.youtube.com/channel/UC0yAsWJZxkLFrogH1Rfa8EA/vid...
[3] http://forum.minecraftuser.jp/viewtopic.php?f=13&t=14837