In Zen practice, the zabuton is the foundation beneath the zafu — the mat that holds the body so the cushion above can hold the mind.
Its wide, flat form is a deliberate act of grounding, distributing weight so the knees, ankles, and shins can soften into stillness rather than brace against the floor.
The deep blue echoes the color long associated with depth, introspection, and the pre-dawn hours when meditation often begins. Where the zafu marks the seat of practice, the zabuton marks its ground.
To sit on one is to acknowledge that comfort and discipline are not opposites. It simply removes the friction of a hard floor, so whatever arises in the mind can be met without distraction.