Hi there. Firstly - I hope that you find some Indian families that home school their kids in Japan - but I think Uco's second link it probably your best bet.
I used to work at one of the better international schools in Japan and have taught quite a few Indian students and have seen what affect these students have in acclimatising to a new culture. If you are not interested in my opinions - it's all good and please feel free to ignore.
At present, there are two international schools based in Japan (Tokyo and Yokohama) which is honestly priced at what I consider an absolutely amazing price for Japan.
http://www.iisjapan.com ($5-6,000 USD for a full time school in Japan a year is extremely cheap)
Most international school are around the $20,000 - $30,000 USD level but you will pay for what you get. As such, students receive a reasonable education but it's not anywhere near the level of schooling a student might receive from a school such as YIS, ASIJ, Canadian Academy or TIS (there are a couple of other very good schools in Japan). However, it would probably be comparable to the so-so schools which also charge the amount mentioned in this paragraph.
The main difference is in the facilities, equipment and level of the staff employed. For the staff employed - this is basically about economics as the best schools in Japan pay a lot more and have a lot more teachers applying for positions as a result. However, the level of teaching I have heard is reasonable and if I was a Western parent and did not have the money (a spare $30,000 USD a year) I would possibly consider sending my kids to the Indian school in Japan.
One thing that I have seen some parents (including western and Indian parents do) is send their kids to Japanese school in elementary to acclimatise them to the Japanese language but then branch out to international or possibly home schooling as they get older.
Being a member of a school is also quite important for western parents (in Japan I consider Indian's western) as it gives them a larger community to associate with. As such - the school becomes both the students and parents (other parents) social group. Never underestimate the importance of speaking to other people who understand your language.
Also note that I understand that every person is different and I have made some generalisations in this reply so not all of the information may be accurate for you individually.
Good luck and I hope you have a fantastic life in Japan.