If you have been with me in this blog or my mailing list, you may remember these gates called « Tori-I ».
Tori means bird.
I, pronounced simply as « i », means being there, or staying there.
So, sometimes I call them « Bird Gate ».
Tori-I is the gate only for the shrine.
Look at the different kinds of Tori-I.
I am not the specialist bur I heard the different styles show different times and religious lines.