If you are planning a trip to Japan during winter, one thing often surprises first-time visitors: it can feel colder than expected. While the temperatures are not always extreme, many buildings, temples, and traditional houses are only lightly heated. That’s why one essential Japan winter travel tip shared by locals is surprisingly simple— kairo (カイロ) . Small, affordable, and incredibly practical, kairo are disposable heat packs that help Japanese people stay warm throughout
