What MMOs influence Sword Art Online and Log Horizon? I see that in SAO and LH, players can craft, buy houses, adhere to the holy trinity of MMO, etc. My first thought was that they might have WoW in Japan, but it doesn't seem to be as popular as it is in the U.S. There don't seem to be a lot of Western MMOs that allow you to buy property either. My second guess is that they might have been heavily influenced by Korean MMOs such as Ragnarok, but I have not played them and I wasn't sure.

So what MMOs could have influenced SAO and LH?
His main inspirations would be

Ultima Online
Ragnarok Online


Reki Kawahara was in the Manga Studies Club. He drew manga and illustrations during his time there. Kawahara would often head to the arcade with his fellow members to play fighting games . He also started playing online games in 1998, starting with Ultima Online. Kawahara also played Ragnarok Online, his most played game (although he stated World of Warcraft during Sakura-Con 2013)
He felt it would be more natural to write about net games.

For some more of his inspirations and why he decided to write you can read a brief biography about him