"Eye of Tsukiyomi" is a dream ritual Kimiko, the empress casts on Kuroneko (the shougun) for his request. He is trying to remember his past, details that might help him to figure out some things.
The only tiny problem is that this way he is quite vulnerable to the empress and she hasn't decided yet if she likes him more dead or alive. XD;
But he was willing to take this risk for the valuable information.

_{On a side note: "Eye of Tsukiyomi" is not taken from Naruto. Tsukiyomi is the god of moon in shinto is all.}