和訳は英文の下にきますが、現在作業中です。 / The Japanese translation is under construction and will follow the English text.
Two “Labor Issues”
Contents
1. Two "labor issues"
2. Ground water in mines
3. Drainage laborers from outside
4. The "mujuku" people
5. Koreans began to work in Sado
6. Koreans in Sado 1939-1945
1. Two “Labor Issues”
Long ago, Sado Island was a place for banishment.
From the ancient time, the government sent political losers there. Some were emperors, their relatives and aristocrats, some government officials, high-ranking monks, scholars, and so on.
Later, criminals were also exiled to Sado.
All these people had to make a living by themselves until they were forgiven and called back. Some died before then, of hunger, of frustration, sickness, loneliness…there are sad stories about them, we may tell them in another post.
In Sado, there were historically two labor issues well-known today. However, the people forced to work in the mines were NOT those who were politically banished or the criminals.
One group were the “mujuku” or vagrant people in Edo period, and the other Koreans in Showa Period. In this post, we will briefly describe them and their circumstances.
2. Ground water in mines

Japan developed unique techniques in mining and dressing solely by manual labor during the era of its isolation.
It means that they just dug by hand haphazardly, or without a plan. By mid 17th Century, therefore, mining was already sluggish, and they still kept digging. Incessant ground water troubled the miners, particularly when the end of the mine was lower than the sea level. At times a copious amount of water gushed from where they had just dug, quickly gathered, and caused the miners to drown.
Therefore, the management assigned drainage to some laborers in the mines. The job was to remove the water collected in mines and pump it outside. It was well-paid but very dangerous and strenuous. The laborers worked on a 24-hour shift. It means one would work a whole day and night in the deepest part of the mine with no ventilation. As for the light, only available were fish oil lamps which gave off horrible odor; one could die of carbon monoxide poisoning. In addition, most workers suffered from silicosis for the rest of their lives.
There was a high turnover with water laborers by quitting, injury, sickness and death, and the management had a hard time to find replacements. They assigned the job to local farmers’ communities but farmers wouldn’t show up. The rumor had been around: Drain in the mine just three days, and you will ruin your back. Beware!
Many people would come over to Sado from other parts of Japan to find a job. However, they knew drainage was the nastiest job and didn’t apply for it. The management even hired agents to recruit people from outside Sado, but securing drainage workers was never successful.
3. Drainage laborers from outside
To solve the chronic problem, in 1878, the government decided to send some vagrant people in Edo and other big cities to Sado and use them as drainage laborers.
During Edo Period, important mines in various parts of Japan were under the government’s direct control. But it was only to Sado that they sent the vagrant people, called mujukus. It was probably because of the difficulty to escape from the island. Sado is 34 km (20 miles) away from the mainland.
The drainage job was so strenuous that hardly any one completed their “contract” alive and made it to home with what money they had earned.
A former Sado magistrate observed in his memoire that no one among the drainage laborers was over forty years old. In three to five years after they arrived and began working, they became skeletal and died. They coughed frequently and spat something like soot before they died, most likely due to silicosis.
4. The “mujuku” people
The Edo government classified homeless people into several categories. Among them, the mujukus were not criminals but their names had been deleted from the family register book they kept for census.
A mujuku’s situation could be as follows: A young man had a problem with his family, by being lazy, rebellious or whatnot. When the family elders got too annoyed, the requested that his name be deleted from the family register; it was a sort of disowning. Without the support of the family and therefore of the community, he couldn’t stay in his hometown. He headed for a big city, particularly Edo, where he should earn some food. Here was a new mujuku.
From the onset of Edo Period, the government tried to control the influx of people into Edo in vain. Thus, in 1877, an official came up with an idea to kill two birds with one stone; whisking some mujukus away from Edo and other cities and using them in Sado.
The target of this homeless hunting was young, healthy men. They arrested them without a warning and put them in a basket individually like a criminal, and sent away. There was no judgment or legal procedure. Once in Sado, the Commissioner’s Office ordered them to work with “a contract”.
The Sado office didn’t even have to report to Edo when those laborers died of sickness or in an accident on the job. After all, they were not in the family register.
As a result, we don’t know exactly how many and who the Edo government sent to Sado. They say the number was about 1,800. Today, there are twenty-eight graves in Sado of those laborers.
5. Koreans began to work in Sado
After Meiji Period began in 1867, Koreans also worked in the mines in Sado and in other parts in Japan.
At the end of the 19th Century, three Koreans graduated from Sado Mining School for young engineers. The other Koreans who came afterward were all laborers.
In 1910, Japan colonized Korea. Between 1902 and 1929, it seems about 3% of the workers were Korean. We don’t know the number of Korean laborers for about 10 years after that. These Koreans were mostly farmers who suffered from bad harvests back in Korea, so once the hard time was over, they returned to Korea.
The situation changed in 1939. Japan expanded aggressive activities in China, and the Japanese government decided to mobilize Koreans from the Korean Peninsula for labor in mines and civil engineering work in Japan.
At that time, a lot of Japanese miners suffered from silicosis. Planning to send Japanese men in good health to the war in China, the Japanese government wanted to assign Koreans to work particularly inside the mines where most workers got silicoses and risks of other health hazards were higher.
6. Koreans in Sado 1939-1945

1939-1945, Koreans were
sent to Sado from rural
areas. Photo credit: By
derivative work: Emok
(talk)Pacific_Area_-
The_Imperial_Powers_1939–
Map.svg: *derivative work:
Emok (talk)World2Hires_filled
_mercator.svg: EmokImage:
Pacific_Area–The_Imperial_
Powers_1939–Map.jpg –
Pacific_Area–The_Imperial_
Powers_1939-_Map.svg,
CC BY-SA 3.0, https://commons.
wikimedia.org/w/index.php?curid=4519919
Between 1939 and 1945, total of 1,200 (some say more) Koreans worked in the Sado mines. First it was a voluntary recruitment from rural areas which were suffering from drought, but later it became more like drafting. Those who worked thus in Sado said later that the assignment from the local office, connected to the Japanese Governor-General’s Office, was mandatory and they couldn’t have refused.
Their contract was for two to three years, but the Mitsubishi management had discreetly planned and prepared to have them stay for good. They also tried to have them invite their families from Korea. When the contract was matured, all Korean laborers were ordered to continue working.
Since the 1920’s, Japanese miners had had labor disputes with mining companies about the poor conditions. By the same token, the standard of living and working conditions that Mitsubishi offered Koreans was low. Korean workers didn’t feel like staying for more than necessary, also because some Japanese managers and colleagues had discriminatory feelings against them.
Between 1939 and 1945, at least ten Korean workers were killed in accidents on the job, three sent back to Korea as ringleaders of labor disputes, and 148 ran away from the mines. For fear that Koreans would soon run away when given cash, the management made them send the pay to their home in Korea, or forced them to save with the company.
In 1945, Japan lost the war. Most Koreans returned to Korea by the year-end. However, many didn’t receive the money Mitsubishi made them to entrust. The amount they didn’t return to the laborers, 231,059 yen and 59 sen (about today’s 1.5 million yen) was deposited at the Aikawa Office of Niigata Prefecture Justice, and ten years later, admitted to national treasury as statute of limitations expired.
[End of the English post]
***********************************************************************
For more on Sado Gold Mines, please continue to read:
=> 1. Visit to Sado Gold Mines
=> 2. Japan’s Gold Before Sado Mines Opened