The horse messenger services in Odenmacho, Kodenmacho and Minami-denmacho are the nerve center of the Shogun's communications network. The official messenger services located in these three towns, supported by horse messengers stationed at each juku (lodging town) along the major highways, can deliver messages to all parts of the country in just a few days. The ability to communicate with all areas of the country by horse messenger allows the bakufu to provide much better administration and support to regional leaders than was possible in the past.
The horse messengers (denma) are essential to Japan's network of communications and transportation, and the three denmacho are the command center for this communications network. The word denmacho means "horse messenger town". When Edo was first built, this part of the city was set aside specifically for the horse messengers to live. As the bakufu (government) grew and developed, the functions of the horse messengers became more complicated, so the area was divided into three separate denmacho, each with its own functions.
The Shogun naturally tries to maintain as much control as possible over the messengers' activities, since communications are very important to the person who runs the country. Each juku is responsible for buying its own horses, feeding and taking good care of them, and supplying riders to carry the messages. However, the management of the lodging towns is handled by the bakufu. Each of the lodging towns has a leader who reports directly to officials in the three denmacho (horse messenger towns).
All three denmacho are located in the same area; just off the main highway and less than one kilometer from Nihonbashi bridge. Odenmacho and Minami-denmacho are responsible for communications and transportation issues along the five main highways of Japan. The riders and administators in these two towns take turns doing the management and delivery work for half a month at a time. In the first half of the month, Odenmacho handles all official writs and messages from the government, while Minami-denmacho handles private messages. In the second half of the month, Minami-denmacho handles the official messages while Odenmacho delivers the private mail and parcels.
Kodenmacho, meanwhile, handles all matters related to local communications and transport within Edo and on the smaller roads close to the city. In addition to horses and riders, all of the denmacho also have foot messengers, known as hikyaku (literally "flying feet"). Kodenmacho relies on these men, more than the other two towns, because local messages do not necessarily need to be sent by horse to arrive there quickly.
The horse messengers at the three denmacho carry messages and parcels, just like the riders at each of the juku towns. However, their job is much harder because they have to handle traffic on all the main roads, instead of just one. Packages are carried from Odenmacho and Minami-denmacho to Shinagawa (on the Tokaido highway), Senju (on the Oshu Kaido), Itabashi (on the Nakasendo) or Takaido (on the Koshu Kaido). In addition, the denmacho do not have a specific number of horses that they are required to provide, but they ARE expected to deliver all messages when asked. This means that they have to have plenty of extra horses and riders, just in case they are needed. They may even be asked to provide riders to work temporarily at some of the juku in cases where the volume of messages is too great, or if horses and riders at the juku are sick or injured and can't work.
Since they are "not allowed" to run short of horses and riders, and have to be prepared for any emergency, the managers of the denmacho maintain large stables in the area between Odenmacho and Minami-denmacho. The long rows of stables, with their musty scent of horsehair and manure, face onto a large, grassy central square. Not only are the horses kept here; all of the riders live at the stables as well, when they are on duty. That way, they are always ready to quickly mount up and be on their way with a message. The central square is used as an exercise ground where horses can get some exercise even when there are no messages to be carried.
In addition to the main stables in the center of the city, the messenger services maintain their own horse pastures for spare horses in several other locations on the outskirts of Edo. These rural stables are mainly used for older horses, mares with young colts, and for horses that are sick, injured or just worn out from too much riding. They are also used as training centers, where young horses are trained to be denma (messenger horses). In an emergency, though, even these animals can be pressed into service.
Although their work is very tiring and strenuous, the messenger horses are well cared for. They are carefully groomed every day, and fed extremely well. Horses are considered extremely valuable, and therefore they are often cared for even better than the men who ride them.You can always find another person to be a rider, but it is hard to find a good, strong and reliable horse.
Some horses are bred and raised at ranches in the outskirts of Edo, but the best horses generally come from northern Japan, or from Shimosa and Kazusa -- the hilly provinces just to the east of Edo. The grassy hillsides in these areas are ideal for raising horses, and the animals grow up strong and swift. The horses raised in the suburbs tend to be weaker animals, and are generally used only for the short-distance messenger services in Kodenmacho
The messages sent by horse are usually written on a long strip of paper which is then folded up several times and sealed with wax. The sender then stamps their own private seal on the wax so that nobody can open the letter and read it without breaking the seal. This is a good way to ensure privacy. If the seal is broken when it arrives at its destination, it is obvious that one of the messengers must have broken the seal. Since each juku keeps careful records of who is working on which day, and what messages they carry, it would be fairly easy to figure out who the prime suspects are if a seal was ever broken. Fortunately, this is rarely necessary. The messengers are highly trained professionals, and they do their job well.
Usually, messages are collected for several hours before they are dispatched, usually at regular hours, two or three times a day. That way, each rider can carry many messages at once. However, in the case of urgent messages, the riders will immediately take the message and ride as fast as they can from juku to juku. Messages with the highest-priority can be carried from Edo to Kyoto or Osaka (about 450 kilometers) in 30 to 35 hours. Considering the many mountains and rivers that must be crossed, this is a remarkably fast communications system. Messages can be sent round-trip to Kyoto in just three days.