The vibrant colours of the brushes used to colour the washi paper glow in the fourth floor. Since 1858 they have coloured and worked with washi paper here in Bunkyo, Tokyo. :) One of the days we went we were lucky enough to see them mixing gold colouring and to see the ceiling full of gold coloured washi paper drying from earlier batches. It made the room glow not only from the reflection of the paper but also the gold dust in the air! :)