The origins of the highway network can be traced to the founding of the ritsuryô state in the 7th century. The Yamato state constructed a series of paved roads, roughly ten meters wide, radiating out from the capital, and traveling roughly in straight lines. The Tôkaidô, Tôsandô, and Hokuriku roads running east and north, along with the San'in-dô and San'yô-dô running west from the capital, and the Nankaidô running south, all had their origins at this time. The Seikai Road, running south from Dazaifu, and one of the only major roads not emanating from the capital, was also built at this time.
The routes of the highways changed little-by-little over time, often by improvements to get around natural barriars. Most of the highways below are still in use and are commonly called by their old names. One normally talks about "Kôshû Kaidô" rather than NR (national route) 20, for instance. The modern expressway network does not follow the old routes, however.
The following route descriptions are not meant to be detailed or to strictly follow Edo-period or earlier routes, but to allow someone with a modern map see how the roads went and what the major barriers were. The indication of the expressways is just to give the reader a general orientation, as those are usually easy to find on maps.
The "Five Highways"
The chief roadways of the Edo period were the so-called Gokaidô 五街道, or "Five Highways." These included four major highways which started at Nihonbashi in Edo (modern Tokyo), one more which branched off of these, and eight auxiliary roads. Even where highways ran through a daimyô's domain, they fell under the jurisdiction of the shogunate; the shogunate also effected and paid for the maintenance of the highways.
Some records indicate that many sections of the road were quite well-maintained. Ditches running along the sides of the roads were maintained to help drain off water, sand was spread over the roads when they were wet, and in hot, dusty weather, water sprayed to settle the dust. In certain sections in the mountains, stones were carefully placed to help increase traction and prevent mudslides, while also providing for effective drainage. In other sections, rows of trees (often cryptomeria, aka sugi) were planted, providing shade for travelers and helping to prevent erosion. Distance markers were placed one ri apart along the road, and other markers or signs indicated major junctions. The roads were also commonly swept and cleaned when an important party, such as a daimyô's sankin kôtai procession, or a foreign embassy, was expected to be passing along that section of road.
Though it is commonly cited that wheeled carts were banned from the roads of Tokugawa Japan, there is no documentary evidence for such a statute. That said, it is known that carts only appeared on certain sections of road and in certain cities. If there was such a ban, it would have served to protect the roads from the ruts and other damage created by wheels, to prevent blockage of the road resulting from spills and the like, and to protect the livelihoods of packhorse operators, who may have petitioned or otherwise voiced their desire for such a ban.
The system contained fifty-three sekisho (barriers, or checkpoints), and 248 post-stations, or shukuba, which ranged in their spacing; in some parts, it was roughly 12.1 km from one station to the next, while in other parts it was only around 4.2 km.
These post-towns were run chiefly by commoners, who were able to make personal profit in charging for lodging, horses, porters, and other forms of labor and services; however, they were required to give priority to shogunate and samurai business, and thus commoner travelers, including merchants attempting to bring goods to market, for example, were forced to either suffer considerable delays in their access to inns, horses, porters, and the like, or to seek alternative, sometimes illegal, travel routes. Despite official prohibitions on commoners riding horses, however, this was scarcely enforced, and commoners who could afford to pay did regularly hire horses, palanquins, and porters.
(From Tokyo to Okazaki [east of Nagoya] the Tomei Expressway; for the whole route, basically NR 1) The Tôkaidô (lit. "Eastern Sea Road") was most famous of the highways, running roughly 300 miles from Edo (Nihonbashi) to Kyoto (Sanjô-Ôhashi), mostly along the Pacific coast, but cutting across the neck of the Izu Peninsula, where the famous Hakone check-point was located. Prior to the construction of Nihonbashi in 1603, the Tôkaidô was considered to begin in Kyoto, and to end, vaguely, somewhere in the Kantô Plain; following the construction of Nihonbashi, the conceptual direction was reversed, with Edo (Nihonbashi) becoming the beginning point of the road, and Kyoto the end point. Though already existing previously in some form, the Edo period Tôkaidô is considered to have been completed in 1624. It typically took about 13 days to walk the Tôkaidô on foot.
The most formidable natural barrier along the Tôkaidô lay just west of Nagoya, where many great rivers - the Kiso, Ibi, Nagara, Hida, among others - flow directly or indirectly into Ise Bay 伊勢湾. Beyond this point, the highway went west from Yokkaichi 四日市 through the Suzuka Pass 鈴鹿峠, and was joined at Kusatsu 草津 by the Nakasendô highway.
The highway made no attempt to cross the rivers, but rather left travelers to take ferries across. Regulations were put into place, however, requiring that travelers cross at these designated crossings, and not at other locations up- or down-river. In total, the Tôkaidô journey included eight river crossings by ferry, and four rivers where travelers had to ford the river on their own. Bridges were built and maintained at several other river crossings along the route, where the bridges were less likely to be lost in flash floods.
The 57 stations of the Tôkaidô were located an average of 8.4 km apart from one another; a survey conducted in 1843 indicates that at that time each station had an average of 55 commoner inns (hatagoya) and an average population of 3,950. The road originally ended at the Sanjô Bridge over the Kamo River in Kyoto, but four additional stations were later added. This extension, known alternatively as the Ôsaka Kaidô, Kyôkaidô, or simply considered an extension of the Tôkaidô, ended at Kôraibashi in Osaka.
The Nakasendô (lit. "Central Mountain Road"), also known as the Tôsandô or Tôsendô (東山道) and as the Kisô Kaidô (木曽街道), ran from Edo to Kyoto through the interior. Major points included Takasaki (to the northwest of Edo), the Usui Pass 碓氷峠, Lake Suwa 諏訪湖, the Kiso River 木曽川 valley, and the Sekigahara Pass 関ヶ原峠. The road is considered to have been completed by 1694.
(Kan-etsu [Kantô-Echigo] 関越 Expressway to Fujioka Jct., then to Saku佐久 via the Jôshinetsu 上信越[ Kôzuke-Shinano-Echigo] Expressway, then SW to Lake Suwa 諏訪湖 by NR 142, then Chûô 中央 Expressway to north of Nagoya, where it enters the Meishin [Nagoya-Kôbe] 名神 Expressway, and from there to Kyoto.)
Earlier, the route of the the Tôsendô was somewhat different. Among other things, it joined the Hokkoku-dô at the Shinano Kokubunji in Ueda instead of at Oiwake. Also, the old Usui Pass is somewhat north of the pass on the modern highway.
The 67 stations of the Nakasendô were spaced an average of 5.2 km apart, and in 1843 each had an average of 1,165 residents and 27 hatagoya.
(Tohoku東北 Expressway; NR 4) The Ôshû-kaidô ran north from Edo, to Shirakawa 白河, in the northern province of Mutsu (also known as Ôshû).
Its ten stations were located roughly 7.9 km apart. As of 1843, each had an average population of 1,186 people and an average of 27 hatagoya.
Its 21 stations included Utsunomiya, Shimo-, Naka- and Kami-Tokujira (徳次郎), Ôzawa, Imaichi, Hatsuishi（鉢石), and Nikkô bôchû 坊中. These were located roughly five kilometers apart, and in 1843 each station had an average of 2,264 residents and 39 hatagoya.
(Chûô 中央 Expressway; NR 20) The Kôshû-kaidô or Kôshû-dôchû ran from Edo to Lake Suwa 諏訪湖, where it joined the Nakasendô, passing through Kai province, which was also called Kôshû. The modern NR 20 passes south of Mt. Takao 高尾山 in Tokyo, but this is a route developed for automobiles. The original route went north of Mt. Takao through the Kobotoke Pass 小仏峠, parallel to the route today of the Chûô train line 中央線.
Kai had come under Ieyasu's control in 1582, and during the Edo period the Kôshû Highway was considered a militarily sensitive escape route. Only a few daimyo were allowed to use it; most had to take the longer route of the Nakasendô highway.
There was a barrier at or near the Kobotoke Pass, originally called the Fujimi ("Mt. Fuji-viewing") barrier. Early in the Edo period it was moved a little bit east of the pass, to a site known as Komakino 駒木野. From 1623 four guards were stationed there. A permit was necessary to use the road.
The 45 stations of the Kôshû-kaidô were roughly 4.2 km away from one another; in 1843, each station had an average of 11 hatagoya and 779 residents.
The eight auxiliary roads counted as part of the Gokaidô ("Five Highways") system were the Saya Road (Sayaji), Mino Road (Minoji), Mibu Road (Mibudô), Reiheishidô, Mito-Sakura-dô, Nikkô onaridô, Honzaka dôri, and Yamazaka dôri.
(Highways Linking the Kantô plain and Echigo province)
The Hokkoku Kaidô starts at Oiwake 追分 (in Karuizawa) on the Nakasendô, shortly after the Nakasendô climbs out of the Kantô Plain via Usui Pass 碓氷峠 and enters Shinano province. It follows the Chikuma River 千曲川 west, downstream, passing through Komoro 小諸, Unno-juku 海野宿 (which preserves many Edo-period buildings), and Ueda上田. After the Chikuma River turns sharply to the north and the Sai River enters, the region is called Kawanakajima 川中島; it was the scene of several famous battles, especially the second and fourth battles of Kawanakajima. The castle of Kaizu, later Matsushiro 松代, was near here. At Toyono 豊野 the highway leaves the Chikuma River and follows the Torii 鳥居River upstream, eventually going through the 666 m. Nojiri Saka Pass 野尻坂峠 into Echigo. From there it goes north down the valley to Naoetsu 直江津 (Jôetsu) on the coast, where it joins the Hokurikudô.
(Kanetsu 関越 [Kantô-Echigo] Expressway; local Rd 36 and NR 17) Using Mikuni Pass
Shimizu Kaido 清水街道
(Kanetsu 関越 [Kantô-Echigo] Expressway;NR 291) Using Shimizu Pass
(Meishin名神 [Nagoya-Kôbe] Expressway, Hokuriku北陸 Expressway; NR8) From Kyoto to Etchû province, then north along the Japan Sea coast
- Kôjien Dictionary
- Super Mapple Road Map of Kanto (Shobun-sha, 1999)
- Explanation talk in the Nakasendo Museum, Oiwake (中山道６９次資料館).
- Information sign at the site of the Komakino Barrier
- Amino Yoshihiko, Alan Christy (trans.), Rethinking Japanese History, University of Michigan (2012), 49.
- Luke Roberts, Mercantilism in a Japanese Domain: The Merchant Origins of Economic Nationalism in 18th-Century Tosa, Cambridge University Press (1998), 17n37.
- Hosokawa-ke monjo: ezu, chizu, sashizu hen II, Tokyo: Yoshikawa kôbunkan (2013), 197.
- Constantine Vaporis, "Linking the Realm: The Gokaidô Highway Network in Early Modern Japan," in Susan Alcock et al (eds.) Highways Byways and Road Systems in the Pre-Modern World, Wiley-Blackwell (2012), 90-105.
- Plaques at the Odawara post station.
- The alternate names of several highways as dôchû instead of kaidô stems from an effort by Confucian scholar Arai Hakuseki in the 1710s to "rectify the names" of these highways, which do not run by the sea, and thus he felt should not be called "sea roads" (海道, kaidô). Watanabe Hiroshi, A History of Japanese Political Thought, 1600-1901, International House of Japan (2012), 148.