Because making many mistakes in the game were considered shameful, kaioi became a means to learn morals and kaioke had been one of a bride's household articles in high society until the Meiji Restoration.
幾度も間違えることは恥辱であるとされ、おのずと修身の具ともなり、明治維新前までは貝桶が上流社会の嫁入り道具の一であったという。