Jan Joosten van Lodensteyn (or Lodensteijn; 1556[citation needed]–1623), known in Japanese as Yayōsu (耶楊子), was a Dutch navigator and trader.

[1][3] Jan Joosten left Rotterdam in 1598 on board De Liefde[b] for a trading voyage in five ship expedition to the East Indies.

[1][5][6] Other fellow sailors included the captain of De Liefde Jacob Quaeckernaeck and purser Melchior van Santvoort.

[7] After making it through the Straits of Magellan, they became separated, but later rejoined the Hoop (Hope) off the coast of Chile, where some of the crew and captains of both vessels died in an encounter with natives.

[5][6] The nineteen bronze cannons were unloaded from the ship and, according to Spanish accounts, later used at the decisive Battle of Sekigahara on 21 October 1600 (between Tokugawa forces and their rivals).

He was privileged to wear the two swords of the samurai and received an annual stipend which placed him (along with Adams) among the ranks of the hatamoto or direct retainers of the shōgun.

In a letter dated November 1614, Jan Joosten, as a trader, wrote: 'I report that the Emperor (Ieyasu) is to purchase all cannon and lead'.

He lived in Edo Castle Town, near present-day Hibiya, Chiyoda-ku, so the place was called Yayosu (八代洲) after his Japanese name Yayōsu (耶楊子).

The Jan Joosten Monument, erected in 1989 to commemorate the 380th anniversary of the Japan-Dutch Treaty of Amity, is located on Yaesu Street.