The book was inspired by the the life of William Adams who arrived on a dutch ship Liefde in 1600 he did have have impact certainly leading to the replacement of the Portuguese by the Dutch as trading partners. He also oversaw the construction of two sea going ships one of which voyage as far as Mexico. He adopted Nihon dress and he was accused of going native by englishmen he later met. If Nihon had adopted a different policy (not isolation) it could have colonized the Western US Australia and NZ. The first English colony in the US was 1607. The Liefde cannon may have been used at the Battle of Sekigahara the figurehead of Erasmus (ships original name) is in a Tokyo museum.