Japanese porn industry

I love Japanese porn. May be as an Indian, I find their country life very much similar to us. But I am surprised, though Japan is a small country compared to India, there are so many beautiful porn actresses there.I find men are fewer. The way they indulge in sexual acts like having sex with old men, tongue kissing and even licking their nether holes, surprise me. I am curious to know more about how they go about making these films. Can any body write about this?