This is Gunze F04 Aqueous Surfacer 500

Aqueous Hobby Color is a very safe paint which has a high degree of user friendliness.
Aqueous Hobby Color paint can be diluted with water if desired, while paint brushes can be cleaned and washed out in water. Ensuring that this is beforethe paint is dry.
The solvent contained in Aqueous Hobby Color paint is very mild.
It provides a glossy texture and very good levelling qualities (ie the smoothness of coated film of paint), resulting in a very good level of painted finish