This article explores the history, causes, prevalence and cultural significance of twins in Japan. Twins are relatively rare in Japan with a twinning rate of only 8.7 per 1,000 births compared to the global average of 16 per 1,000 births. Causes for this low rate are not fully understood but could be related to age-related fertility issues or certain genetic factors. In Japanese culture twins have long had a special significance and today they are still celebrated with festivals and rituals. Recently there has been an increase in twinning rates among Japanese women aged 35-39 years old which could be due to increased access to fertility treatments such as IVF. However, raising twins can present challenges such as financial pressures or social isolation so families should be aware of these potential issues when preparing for twin children.