The myths in Shinto are written in the old literatures - Kojiki, Nihonshoki and Fudoki, which were written in early 700s AC.
Here is a myth named `国産み(Kuniumi)' , which is about the beginning of Japan.
Gods in heaven ordered Izanaki (male) and Isanami (female) to create lands and gave them a sward. They stirred the chaotic ocean with it from the bridge connecting the heaven and the earth, and then, a drop of seawater bacame a land, named `Onogoro jima (Onogoro island), which was the very first island of Japan.
There is a tiny island called Eshima in northern part of Awaji island in Hyogo prefecture, and it is said to be Onogoro island.
The story continues. Those two gods became a couple on the Onogoro island and Isanami bore 8 islands like babies. The first one was Awaji island (Hyogo prefecture).
The others are Shikoku island, Oki island (Shimane prefecture), Kyushu island, Iki island (Nagasaki prefecture), and a part of Honshu island in order.
This is the beginning of Japan.
As they also created some gods after the lands, there is another myth about that.
So they are enshrined at many shrines as the god of creation.
Especially, Izanagi jingu shrine in Awaji island is the oldest shrine in Japan, which is of course a shrine for Izanagi god.