 The zabuton used are supposedly extra-heavy ones weighing 4 kg (9 pounds), so even a stack of ten or more will not topple.Should an ogiri member acquire 10 zabuton, he is entitled to that day's special prize, which is usually related to a famous quote, such as 'Boys, Be Ambitious'.Since Utamaru was notoriously keen on removing zabuton, especially from the intelligent yet arrogant Enraku, it is very rare for anyone to actually achieve the magical 10.