A fukuro obi is a formal Japanese obi, often worn with kimono at special events. It is typically 4-4.5 meters long and about 30 cm wide, with designs on one side only, making it lighter and less expensive than the fully patterned maru obi. The fukuro obi features elaborate patterns, often including gold or silver threads, and is tied in various formal knots like the taiko musubi. It’s suitable for occasions such as weddings and tea ceremonies.