I didn't bother to read the DaVinci code but I did see the movie. I took it as sheer entertainment. When I'm looking for real answers I go to the Jesus Code. Kjv or nkjv.
What's all this talk about maybe Jesus was a sinner? If that were the case, no one's salvation would be valid, and would make the Father unjust and a liar? Uhh, that's the wrong path for sure.
By one man, sin entered the world, and corrupted all. By one sinless man accepting the punishment for sin, all were acquitted (potentially, if they choose to accept)
Anything else would be an unjust court.
Also, Jesus didn't have time to move to Japan and raise a family after his crucifixion. He was only here for 40 days (pretty sure) before He ascended back to heaven, so that idea is tripe too.
Jesus was a carpenter. It takes a bit of time to gain a work reputation and gain noterity. Scripture says He had that, so Jesus must have remained fairly stable and remained in the same region while playing His trade.