The SPIKY series dares to approach the flat modern way of looking at things with a sense of foreignness.
The sake cups are painted with positive words such as "Get Stand Up," "Stay Gold," and "Silver lining" in imitation of graffiti. This is Koga's message to the world suffering from the coronavirus pandemic.

The studs that cover the entire piece are punk, and the graffiti is street culture, and these are captured on the canvas of sake vessels, which have developed in Japanese culture.
Its distinctive shape is as if it refuses to be picked up.
The "studs" that protrude from the container are visualizations and touchables of the power inherent in objects. The work is a powerful expression, as if the power hidden within bursts to the surface.

Ceramics are a traditional craft that has been cultivated over a long history. Koga intends to give a fresh surprise to the person who holds it by providing a formative stimulation to it.