The firearms they introduced subsequently had a great impact on the unification of Japan, and the following era of trade spurred economic development.

The Portuguese legacy in Japan includes, among other things, the Nanban art and the gastronomic heritage (such as the national dish tempura or various confections such as konpeitō, keiran sōmen and castella cakes from Nagasaki), but also the linguistic heritage, which is reflected in several dozen Portuguese loanwords in the Japanese language in geography, religion and everyday culture, for example bread.

This period of time is often entitled Nanban trade, where both Portuguese and Japanese would engage in mercantilism and cultural exchange.

The Portuguese at this time would found the port of Nagasaki, through the initiative of the Jesuit Gaspar Vilela and the Daimyo lord Ōmura Sumitada, in 1571, where the annual trade ships arrived from then on.

In 1592 the Portuguese trade with Japan started being increasingly challenged by Chinese smugglers on their reeds, in addition to Spanish vessels coming to Manila in 1600, the Dutch in 1609 and English in 1613.

Oda Nobunaga, a famous daimyo who nearly unified all of Japan, made extensive use of guns playing a key role in the Battle of Nagashino.

The Japanese soon worked on various techniques to improve the effectiveness of their guns and even developed larger caliber barrels and ammunition to increase efficiency.

The weapons were extremely important in the unification of Japan under Toyotomi Hideyoshi and Tokugawa Ieyasu, as well as in the invasions of Korea in 1592 and 1597.

Europeans brought by trade not only weapons, but also clocks, soap, tobacco, and other unknown products in Feudal Japan.

The Jesuits initially missionized exclusively, then in competition with other Christian monastic orders, but also significantly promoted cultural, scientific, institutional, business and diplomatic exchange.

In addition to the religious aspect, European culture was taught there in many areas, including music, theater, [[painting and Western art, later known as Nanban_art.

They published printed matter in Latin, Portuguese and transcribed Japanese, sharing knowledge in the fields of cartography, astronomy, medicine, military strategy, and gastronomy.

The Portuguese missionary Cristóvão Ferreira, who arrived in Japan in 1610, contributed to the tense situation on the issue with his varied role until he was executed there around 1650.

Wenceslau de Moraes in particular made a great contribution to the Portuguese presence in Japan as a diplomatic and economic mediator.

After the war, nine countries, including Japan and Portugal, attended the Washington Naval Conference of 1922, where they both ratified the Nine-Power Treaty.

To varying, degrees, however, both Macau and East Timor later came under de facto control of Japan, until the end of the war.

Nevertheless, Portugal did not object, when Australian and Dutch forces landed unilaterally in East Timor, to set up defensive positions.

In the subsequent Timor campaign, the indigenous Timorese and other Portuguese subjects assisted the Allies and suffered reprisals from Japanese forces.

Soon afterwards, Japan issued an ultimatum to Portugal, demanding that the territorial government accept the installation of Japanese advisors, and threatening direct occupation.

Believing that Japan had or would get access to stores of aviation fuel in Macau, US forces launched several air raids on the territory.

In 1998, the Lisbon World Exposition was held under the theme "The Oceans: a Heritage for the Future", with Emperor Akihito and Empress Michiko making their first visit to Portugal.

Special Envoy Taimei Yamaguchi Parliamentary Vice-Minister of Economy, Trade and Industry Masaji Matsuyama Minister of State Tomomi Inada [7] Governor at Banco de Portugal Carlos da Silva Costa Minister of Internal Administration Anabela Miranda Rodrigues Prime Minister Pedro Manuel Mamede Passos Coelho Minister of Foreign Affairs Rui Manuel Parente Chancerelle de Machete Minister of Economy António Pires de Lima Minister of Environment, Spatial Planning and Energy Jorge Manuel Lopes Moreira da Silva Secretary of State of Internationalization Jorge Costa Oliveira Secretary of State of Internationalization Eurico Jorge Nogueira Leite Brilhante Dias Ex-Presidente Aníbal Cavaco Silva (Ceremony of Enthronement) Secretary of State for Energy João Galamba [7] Unlike in the 16th and 17th centuries, the current relationship between the two countries has little influence on each other's political situation, and economic ties are also relatively small.

[10] In February 2011, Nissan started construction of a plant to produce lithium-ion batteries for electric vehicles in Aveiro, Portugal.

Portugal was the first European nation to have direct negotiations with Japan, and the cultural artifacts imported at that time, such as buttons, playing cards, wine and several Japanese sweets and foods (such as tempura, konpeito, and castella), are still called by names of Portuguese origin and have left a legacy that has become entrenched in Japanese society.

Particularly worth mentioning is "Portugaru San – O Sr. Portugal em Tokushima" shot in 1993, a film about the Portuguese diplomat and author Wenceslau de Moraes.

In 1996, João Mário Grilo made "Os Olhos da Ásia", a film about the history of the Portuguese Jesuits in Japan.

[15] In 2016, the Portuguese director Cláudia Varejão portrayed the everyday life of three women who have been diving together in a small fishing village on the Shima Peninsula for 30 years with her documentary Ama-San.

The Portimonense SC club particularly frequently signs players from Japan, including Mū Kanazaki, Shoya Nakajima, Takuma Nishimura, Shiryū Fujiwara, Kōki Anzai and most recently Kodai Nagashima and Hiroki Sugajima.

Judo has been practiced in Portugal since a demonstration by two officers of the Imperial Japanese Navy while anchored in Lisbon in the early 20th century.