"The first two Europeans to reach Japan in the year 1543 were the Portuguese traders António da Mota and Francisco Zeimoto and possibly Fernão Mendes Pinto and also introduced Firearms to the Japanese.

The Japanese were already familiar with gunpowder weaponry ,and had been using basic Chinese originated guns and cannon tubes called "Teppō" for around 270 years before the arrival of the Portuguese. In comparison, the Portuguese guns were light, had a matchlock firing mechanism, and were easy to aim. Because the Portuguese-made firearms were introduced into Tanegashima, the arquebus was ultimately called Tanegashima in Japan.Due to the inclusion of the matchlocks the course of the Senguko Jidai was changed as was the future of japan altogether.

Within a year after the first trade in guns, Japanese swordsmiths and ironsmiths managed to reproduce the matchlock mechanism and mass-produce the Portuguese guns. Barely fifty years later, "by the end of the 16th century, guns were almost certainly more common in Japan than in any other country in the world", its armies equipped with a number of guns dwarfing any contemporary army in Europe . The guns were strongly instrumental in the unification of Japan under Toyotomi Hideyoshi and Tokugawa Ieyasu, as well as in the invasions of Korea in 1592 and 1597. The daimyo who initiated the unification of Japan, Oda Nobunaga, made extensive use of arquebuses in his campaigns."