In Japan, the practice of sleeping arrangements for married couples has evolved over time. Traditionally, it was common for couples to sleep in separate rooms or even separate houses due to the belief that it was easier to maintain purity by avoiding physical contact during sleep. However, as Japan became more westernized after World War II, the practice of sleeping together became more common. In recent years, there has been a shift towards couples sleeping together in Japan. While there are benefits to sleeping together such as emotional intimacy and better sleep quality, some couples still prefer to sleep separately due to snoring or different sleep habits. Ultimately, what works best for a couple depends on their individual needs and preferences.