A Platinum Izumo Togi Yakumonuri. In this image it is the lower pen.
The decoration on the Togi Yakumonuri is based on one of the ceiling paintings at the Izumo Shrine. The technique used in this case is to paint the clouds as a series of layers with color on color that is then ground down reveling the underlying colors and the whole polished design the covered by several coats of clear urushi.
Closeup showing details of the two techniques:
This particular pen has the broad nib.