When Europeans first came into contact with the New World in the 15th century, the course of food history shifted. The vast continents of the Americas offered a wealth of previously unknown foods to the explorers. There were some foods, such as wheat, that the newcomers had brought with them and introduced into these lands, but there were many more food items that the sailors took back home with them and, on the way, broadcast those seeds around the globe.
It is hard to imagine Irish cooking without the potato, Italian with no tomatoes or fiery Thai food lacking chilies, but all of these foods and many more originated in North or South America, lands virtually unknown to the rest of the world before 1492. Some food crops were intentionally introduced into new places and climates with an eye for profit, while others were spread around the globe as stowaways aboard the ships that sailed from port to port.
During this period of food trading and adaptation, foods from the Americas and Europe trickled into Japan as well. Many foods came by way of European missionaries and merchants, a few others by Japanese explorers in Asia and by other foreign travelers to the country. Additional foods entered later, when the Americans demanded the opening of Japanese ports in the 19th century.