Mukai Tadakatsu more generally known as Mukai Shōgen (Jp:向井将監), was the Admiral of the fleet (Jp:お船手奉行) for the Shōgun

Shogun

A was one of the hereditary military dictators of Japan from 1192 to 1867. In this period, the shoguns, or their shikken regents , were the de facto rulers of Japan though they were nominally appointed by the emperor...

 Tokugawa Ieyasu

Tokugawa Ieyasu

 was the founder and first shogun of the Tokugawa shogunate of Japan , which ruled from the Battle of Sekigahara  in 1600 until the Meiji Restoration in 1868. Ieyasu seized power in 1600, received appointment as shogun in 1603, abdicated from office in 1605, but...

 during the beginning of the Edo period

Edo period

The , or , is a division of Japanese history which was ruled by the shoguns of the Tokugawa family, running from 1603 to 1868. The political entity of this period was the Tokugawa shogunate....

, in the early 17th century.

Between 1604 to 1606, under the order of Tokugawa Ieyasu, Mukai Shogen, who was Commander in Chief of the Navy of Uraga

Uraga

is a subdivision of the city of Yokosuka, Kanagawa Prefecture, Japan. It is located on the south eastern side of the Miura Peninsula, at the northern end of the Uraga Channel, at the entrance of Tokyo Bay.-History:...

, built Japan's first Western sailship together with William Adams

William Adams (sailor)

William Adams , also known in Japanese as Anjin-sama and Miura Anjin , was an English navigator who travelled to Japan and is believed to be the first Englishman ever to reach that country...

 and carpenters from the city of . The ship was 80 tons, and allowed them to survey Japanese coasts. A second, larger ship of 120 tons, capable of sailing on the high seas was again ordered by Tokugawa Ieyasu. She was later lent in 1610 to a Spanish embassy, and crossed the Pacific Ocean. She was named by the Spanish San Buena Ventura.

He is then recorded as having participated to the preparation of the embassy of Hasekura Tsunenaga

Hasekura Tsunenaga

Hasekura Rokuemon Tsunenaga or was a Japanese samurai and retainer of Date Masamune, the daimyo of Sendai....

 to America and Europe in 1615, by giving his support to the mission and supplying his Chief Carpenter for the building of the San Juan Bautista

San Juan Bautista

San Juan Bautista is:* The Spanish-language name of Saint John the Baptist. See also the disambiguation page at San Juan. The name also may appear as a Spanish translation of the French Jean-Baptiste.As a toponym, San Juan Bautista may refer to:...

.

He is also reported by Richard Cocks

Richard Cocks

Richard Cocks was the head of the British East India Company trading post in Hirado, Japan, between 1613 and 1623, from its creation, and lasting to its closure due to bankruptcy....

, head of the English Factory in Hirado, to have discussed with him and William Adams

William Adams (sailor)

William Adams , also known in Japanese as Anjin-sama and Miura Anjin , was an English navigator who travelled to Japan and is believed to be the first Englishman ever to reach that country...

 an invasion of the Philippines

Philippines

The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...

by Japanese forces in 1616.