What is the official currency of Japan?

The official currency of Japan is the Japanese Yen, denoted by the ISO code JPY and the symbol ¥, issued and regulated by the Bank of Japan, the country's central bank. The yen was introduced in 1871 under the New Currency Act during the Meiji era, replacing the earlier complex system of feudal-era coinage used under the Tokugawa shogunate, and it standardised Japan's monetary system on a decimal basis similar to Western currencies of the time. Today the yen is one of the most widely traded currencies in global foreign exchange markets and is considered a safe-haven currency during periods of international financial uncertainty. It is the correct answer here because it is the sole legal tender across Japan for all transactions, government accounting and international trade invoicing involving the country. The South Korean Won is incorrect because it is the legal tender of South Korea, a separate East Asian nation with its own central bank, the Bank of Korea, and the two currencies are entirely independent despite regional proximity. The Chinese Yuan (Renminbi) is incorrect because it belongs to China, issued by the People's Bank of China, and while China and Japan are major trading partners, their currencies are not interchangeable or linked by a common monetary authority. The Malaysian Ringgit is a clearly distant distractor since Malaysia lies in Southeast Asia, far from Japan both geographically and in currency history.