Sengoku -- which came out in 1999 -- was considered by many to be one of the most well-researched and well-written Samurai/Ninja/Chanbara 16th Century Japan of all time, Sengoku is still available online for less than $10.
It was inspired by earlier classics such as Land of the Rising Sun and Bushido, and the then-dominant CCG / RPG property Legend of the 5 Rings. In fact, some of the early work on the RPG was done with the potential of creating Bushido Third Edition in mind, but ultimately the group decided to create a brand new RPG on its own.
What's in it for Fading Suns?
One of the major houses of nobility -- the Li Halan house -- is obviously inspired by more Asian cultures. While it could be argued that there's a stronger Chinese influence (which we can draw from other sources), there's no stopping us from doing the same from feudal Japan.
The first stop would be the "Manners & Customs" section, which tackles things like the different types of bowing (greeting superiors, inferiors, and equals; apologies), different levels of politeness and address in speech, removal of footwear when going indoors, audiences with personages (important for meeting the Dukes of a House), clothing for males and females of all stations, sword / weapon etiquette for posturing, entering buildings, traveling with weapons, and so on.
The next stop would be the "Daily Life in Japan" section, which holds useful telling details on life in an asian culture like education, various games and sports, types recreational activities performed (beyond Go, there's the card game hyakunin isshu, which involves 100 cards with the last half of famous poems and an illustration + 100 cards with the first half of famous poems and an illustration for joining, a dice game known as Han-Cho, various equestrian activities, and we haven't even discussed martial arts matches yet or the Arts).
Since the overall culture of the Known Worlds would somehow overlay the native culture, you can pick and choose from the "Societal Structures" section, which tackles the Imperial Court, Castes, and Samurai Clan membership, and the Shinobi.
Last, but not least, the "Religion" section. Since it is heretical to believe in any other religion other than that of the Pancreator as revealed by the Prophet Zebulon and represented by the Orthodox Church, all the religions detailed here (Shinto, Buddhism, Shugendo, Ryobu-Shinto, and Christianity) would be mineable as small heretical sects -- fodder for the Inquisition or the Avesti.