The Shiwaku Islands, consisting of 13 inhabited islands, lie in the eastern part of the Setouchi Inland Sea. As the Inland Sea was the oldest water-highway in Japan, the islanders were skillful in ship-building and ship-handling, which were the basis of the coining out of the “Ninzmyô System”.
The “Nimmyô System”, originated in the year 1590 and continued until the end of the Edo Period (Feudal Period, 1603-1867), was established for a group of 650 seamen in order to place them under the direct control of the Shogunate (Military Government). According to the system, they had a duty to engage in the official transportationn by sea in case of need, and were granted, in compensation for their services, the agricultural products in the island by the Shogunate.
Most of the inhabitants of the islands were occupied by Nimmyô and the-ir family, the rest, only a little in number, however, had not the privilege of Nimmyô. They were called Môto against Ninznzyô. It is very important to understand the defference in social standing between Nimmyô and Môto It seems that the class consciousness of the former was so strong that the la-tter was despised unjustly.
The people, belonging to Nimmyô, occupied themselves with the shipping business, which prospered exceedingly in the middle of the Edo Period, butt declined before long. The prosperity of the shipping business was caused by the establishment of a new sea-route of transportation from the Tôhoku District to Ôsaka or Edo by, way of the Japan Sea, and the principal car-go was rice, which was then required in a great quantity with the remar-kable development of the cities (Edo and Ôsaka) and their increased popu-lation.
Though the transportation work was monopolized by Nimnnyô, it began to decline in the Genroku age (1688-1703). The decline may be attributed to the multiple causes. The rise and fall of the shipping business gave intense influences to the economy of the islands. Agriculture had remained only as a side-work of the islanders, so that the economic independence of the isalnds had been lost since the beginnig of the Nimnlyô System. In des-pite of the poor agricultural production, the population of the islands incre-ased. Consequently, with, the decline of shipping busxness, islanders were obliged to go over to the mainland for work. Most of the emigrants worked as carpenter. Only a few, of Nimmyô became fishermen for the fishery of the islands had been carried on almost by Môto.