a.Where do you go when you die?
I think deceased will go to hell or heaven,depend on what they did as they were alive. If they caused bad things, they'll go to hell and if they caused good things, they'll go to heaven.
b.Why do Japanese have death memorial service 1 month, 1 year, 3years, 7years,etc.
The main reason is hold a service for deceased's soul and survivor pray for the repose of soul.
We think deseased will born again and then it takes 49days. Next, every 7 days they will put them on trial by 7 judges. So, survivor have to hold a memorial service every 7 days after they died.
(参照：英語で話す仏教Q&A)
