鎖国とオランダ貿易：出島が開いた窓Bridging Isolation Through Dejima's Dutch Trade
During the Edo period, it is well known that the Tokugawa Shogunate adopted a foreign policy often referred to as “sakoku” (鎖国), severely restricting interactions with foreign countries. However, there is a common misconception that equates the entire Edo period with a closed-door policy. In fact, during the reign of Tokugawa Ieyasu (1543-1616), who unified Japan after a long period of warring states led by the samurai, there was effectively no such closed-door system in place. Discussing sakoku is quite complicated, and rather than identifying a clearly defined period, it is more accurate to consider that the policy gradually emerged after Ieyasu’s death. The underlying reason behind sakoku was anti-Christian sentiment, but I will discuss that separately. In this article, I want to explore why, during the sakoku era, only the Netherlands was permitted to trade with Japan. One significant factor when examining the Edo period is how the Japanese adopted Western culture through the Dutch.
To begin with, the background to the Shogunate’s increasing suspicion towards Christianity involved several complicated, step-by-step events. To briefly summarize: trade relations with the Dutch began during Ieyasu’s reign in 1609. Soon after, in 1612, Ieyasu issued the “Anti-Christian Edict” (禁教令) to restrict the missionary activities of Christian preachers, as the Shogunate saw missionary work, tied to foreign powers, as a threat to domestic order. Later, during the reign of the third shogun, Tokugawa Iemitsu (1623-1651), the first prohibition on Japanese citizens traveling overseas, the “First Overseas Travel Ban” (第一次渡航禁令), was issued in 1633, and further tightened by 1635. As the ban on Christianity combined with heavy taxation, discontent grew among people in parts of Nagasaki and Amakusa, and it erupted in the Shimabara-Amakusa Rebellion (島原・天草一揆) of 1637. However, the Shogunate swiftly mobilized an army of 120,000 troops and decisively suppressed the rebellion.
This event triggered the Shogunate’s firm decision to strengthen the sakoku policy. Thus, Japan’s isolation was built up step by step, not out of a desire to sever foreign trade and relationships, but out of the Shogunate’s wariness toward a system in which missionary work and trade were bound together. Consequently, in 1639, Japan terminated relations with Portugal, where mission and trade were one, fully prohibiting Portuguese ships from entering Japan and completely barring Christian missionary activities, thereby firmly establishing the sakoku system. As a result, among Western countries, only the Netherlands was allowed to maintain official trade relations with Japan.
Why was the Netherlands alone granted this exceptional privilege? The most commonly known reason is that the Netherlands was a Protestant country and did not actively pursue missionary activities aimed at converting other nations, unlike Catholic countries. Indeed, the Dutch officially pledged to the Shogunate that they had no intention of engaging in Christian missionary work, securing continued permission for trade.
Consequently, while other Western nations were expelled from Japan, the Dutch trading post relocated to Dejima (出島) in Nagasaki in 1641. From then onwards, the Dutch merchants were effectively confined to Dejima, a specially designated area during the sakoku period, where they continued trading under strict supervision. Although their annual visits and trade goods were strictly limited, the Shogunate highly valued the trade as an essential window for acquiring Western information and products. Equally, the Dutch were unwilling to relinquish their privileged trading rights despite the restrictive conditions. Moreover, the Dutch adhered faithfully to their promise not to conduct missionary work in Japan, a fact likely contributing to the enduring positive image the Dutch hold among the Japanese even today.
Even during the sakoku period, Nagasaki continued receiving annual visits from Dutch (and Chinese) ships, bringing cutting-edge knowledge and exotic imported goods. Such novel items from abroad captivated everyone from shoguns and daimyo (feudal lords) to commoners, becoming the catalyst for innovative and distinct artistic expressions previously unseen in traditional Japanese painting. Particularly influential were Western paintings introduced through the Dutch, profoundly inspiring Japanese painters. However, as the Dutch in Dejima were strictly supervised, they could not freely disseminate their culture or information throughout Japan. So how exactly did the Dutch-influenced information and culture spread? Behind this dissemination were historical figures whose roles often remain untold.
During this period, the Tokugawa Shogunate prohibited Dutch merchants on Dejima from bringing their wives and children, and to avoid friction with local life, the authorities exceptionally allowed licensed prostitutes, known as “yujo” (遊女), to visit Dejima. These women primarily came from the nearby Maruyama red-light district (丸山遊郭) and uniquely had the privilege of freely entering and leaving Dejima during the closed-door era (sakoku). They played an incredibly significant role by transmitting information and culture obtained from the Dutch beyond Dejima. Yet, because these women belonged to a socially marginalized class, serious academic research into their contributions has been neglected. I myself have investigated this area, and found that the Maruyama district no longer retains any historical remnants, and even local tourism initiatives highlighting Dejima fail to mention these women, causing their historical role to vanish into obscurity.
Nevertheless, the role these yujo played was undeniably significant. Although certainly not responsible for everything, they did facilitate the spread of some realistic Western painting techniques found in imported Dutch oil paintings and copperplate engravings, such as linear perspective (透視図法) and chiaroscuro shading, which were previously unknown in traditional Japanese art. Starting from the mid-Edo period, pioneering artists like Hiraga Gennai (1728–1780) and Shiba Kokan (1747–1818) actively studied copperplate engraving techniques and linear perspective from Dutch books (“Ransho,” 蘭書), integrating precise realistic depiction into their own artworks. This significantly impacted ukiyo-e artists and other Japanese painters at the time, marking the initial stage of Western painting’s acceptance in Japan.
Meanwhile, some artists emerged who, rather than directly imitating Western methods introduced via the Netherlands, adapted and transformed these methods into uniquely Japanese artistic expressions. A leading figure among them was the Kyoto-based painter Ito Jakuchu (1716–1800). Although Jakuchu did not directly copy Dutch paintings, his pursuit of realism indicates indirect influences, suggesting he had some access to Dutch artwork. Indeed, Jakuchu studied the richly colored and shaded bird-and-flower paintings introduced to Japan by the Chinese artist Shen Nanpin (沈南蘋, active mid-18th century), who visited Nagasaki. This exposure likely provided Jakuchu with an opportunity to incorporate foreign painting techniques.
Jakuchu mastered traditional ink-wash painting (水墨画) and classical Japanese-style painting (大和絵), but he integrated novel elements such as three-dimensional shading and meticulous biological depictions, opening entirely new artistic horizons. As a result, Jakuchu’s dynamic compositions of vividly depicted roosters and plants possessed an originality unprecedented in traditional Japanese art. However, during his lifetime, few recognized Jakuchu’s genius, and he famously stated, “My paintings will be understood in 1,000 years,” before his death.
Beyond art, the Dutch trading post in Dejima also served as an important gateway for books and academic knowledge. Western academic disciplines introduced via Dutch texts were collectively known in Japan as “Rangaku” (蘭学, Dutch studies), flourishing significantly throughout the mid-Edo period. A key figure who spurred this growth was the eighth Shogun, Tokugawa Yoshimune (reigned 1716–1745). Yoshimune displayed great interest in useful foreign products and knowledge, and in 1720 relaxed prohibitions on importing non-Christian Western books, thus boosting the popularity of Rangaku. Furthermore, Yoshimune commissioned scholars such as Aoki Konyo (1689–1769) and Noro Genjo (1693–1761) to learn Dutch, fostering an earnest movement to study Western medical and natural sciences through previously incomprehensible Dutch texts. Amid this rapidly developing academic environment, groundbreaking achievements emerged in the late 18th century.
A prime example was the publication of “Kaitai Shinsho” (解体新書, “New Book of Anatomy”) in 1774. Originally a Dutch translation (1734) of the German anatomical work “Anatomische Tabellen” by Johann Adam Kulmus, the text was meticulously translated into Japanese by Rangaku scholars Sugita Genpaku (1733–1817), Maeno Ryotaku (1723–1803), and others, through years of painstaking annotation and translation efforts. Additionally, Odano Naotake, a practitioner of Dutch-style painting (蘭画, Ranga), contributed remarkably accurate illustrations copied directly from Western anatomical diagrams.
Building upon Yoshimune’s initiatives, fields studied through Dutch texts after “Kaitai Shinsho” quickly expanded beyond medicine to encompass pharmacy, natural history (botany and zoology), astronomy, calendar studies, physics, chemistry, geography, and numerous other disciplines. This rapid proliferation of knowledge was partly due to active encouragement from both the Shogunate and local feudal domains, alongside the fact that academic pursuits were generally unrestricted among commoner scholars who did not hold official positions. Consequently, Rangaku flourished widely as scholarly achievements and teachings spread throughout Japan. By the late Edo period, not only Edo and Osaka but also various local domains established Rangaku academies, greatly expanding its regional impact.
Rangaku was chiefly passed down through family lineages like the Sugita, Katsuragawa, and Udagawa families, who also actively compiled comprehensive Dutch dictionaries. Such widespread intellectual diffusion eventually formed the foundations for broader Western scientific knowledge, significantly contributing to Japan’s modernization during the Bakumatsu (late Edo period). Despite the strictness of the sakoku policy, through its sole Western contact, the Netherlands, Western knowledge steadily accumulated and eventually brought about a new cultural horizon for Japan. The very fact that this significant initial exchange between East and West occurred during Japan’s period of isolation is something that merits renewed consideration by all of us today.