Arrival of foreign powers at japan"s ( closed ) door. There are different interpretations of events in history. Japan: sakoku re-examined: only 4 nations were capable of sailing around the world to japan: Spanish, portuguese, dutch, british: the reason for the illusion that japan is in isolation was because of the dutch navy. In order to maintain its control on trade, they shut out these powers. They forced others to stay away, that the. They had to fire at all of them to keep them out. However, that might not work well with future relations with dutch because some of these ships may be dutch. In 1825, seishisai wrote his book new theses: j i means to drive out barbarians - close the doors to anybody/westerners that want to come in. This becomes a national policy: seishisai"s book becomes very influential, in 1825, the expulsion of the don"t think twice, just shoot policy was not irrational.