- Birth: 1569
- Death: 1633
- Japanese: 以心 崇伝 (Ishin Suuden)
- Other name: Konchi-in Sûden (金地院崇伝)
- Titles: Enshô Honkô Kokushi (1626)
Sûden was a Zen Rinzai monk who acted as an advisor to Tokugawa Ieyasu on both religious matters and on foreign affairs. As a result, he played a notable role in those spheres in the foundation of the Tokugawa shogunate.
Sûden was tasked by Ieyasu with recording the shogunate's diplomatic activities and communications; his records were then compiled into the Ikoku nikki (Chronicle of Foreign Countries). He also oversaw the administration of the country's Buddhist temples and Shinto shrines along with Itakura Katsushige, and inaugurated two temples called Konchiin, one in Sunpu, where he made his home, and another in Edo.
In 1612 he was tasked with composing a letter to the governor of New Spain inviting Spanish trade; during his service to the Tokugawa, he would be involved in drafting a number of communications with the Spanish colonies, Korean court, various Ming Chinese officials, and other foreign powers. Negotiations with the Ming court over the reopening of trade between China and Japan, and over the issue of piracy (wakô) formed a significant part of this work. In 1617, and again in 1624, he rejected requests from the Korean court that the shogun be referred to by the term "king" (王, ô) in diplomatic documents; this would imply submission to within the Sinocentric world order, to the Chinese Emperor, and would lead to the identification of Japan as a tributary state to China.
Sûden was instrumental in effecting the edict banning Christianity in 1614, drafted the Buke Shohatto in 1615 along with a number of other scholars, and read the document before an assembly of daimyô at Fushimi that same year. At Ieyasu’s funeral in 1616, he acted as an overseer of ceremonies, along with Tenkai and Bonshun.
He was named Enshô Honkô Kokushi by Emperor Gô-Mizunoo in 1626. His primary work, the Honkô kokushi nikki (Chronicles of Master Honkô), remains a valuable tool for understanding diplomacy of the time.