There were 11 things that the yama folk avoided at all costs.
Sakubei Yamamoto's historical coal mine paintings also include important items of folklore, one of them being the folk beliefs and superstitions of the yama.
It was bad luck to blow a flute, clap, or cover one's ears inside the mines.
Work at the yama involved dangerous underground labor, and thus included certain superstitions to be avoided at all costs – superstitions that would not be found at other workplaces. Sakubei's records note the following 11 taboos.
1 Playing a flute inside the mines
Oyamazumi-nomikoto, the mountain guardian diety, loves music – especially the sound of the flute. He is always seeing to it that disaster is prevented, so it was said that playing his favorite instrument would distract his attention from protecting the miners and cause an accident.
2 Clapping
There was generally no reason to clap or applaud inside the coal mine, but if someone were to do so while joking around, the gods would think someone was praying (in Shintoism, the folk religion of Japan, one claps one's hands several times before a shrine as a prayer offering). Upon hearing the clapping, it was said that the mountain diety, thinking "Oh, I wonder what they are praying for...," would carelessly loosen his hand from supporting the mine ceiling, causing a cave-in. It is also said that the clapping sound was a danger as it might have been mistaken for the sound of the kamisashi inserted at the top of the pillars supporting the ceiling breaking.
The body of the deceased was carried up out of the mine to ensure that his or her soul would not be left inside the mine.
3 Covering one's ears
The ears proved superior tools to the eyes for sensing danger in the dimly lit coal mines, so one would always want to keep them open. If there were an unfortunate accident causing a death inside the mine, the body of the deceased would be carried up out of the mine while calling out their name so as not to let their soul get trapped inside. Everyone made sure to wear their headgear in a way so as to be able to hear their mates' voices loud and clear.
4 Wearing geta (traditional wooden sandals)
With the steep inclines inside the mines, even with the most appropriate footwear there was still the danger of stumbling and getting injured. Wearing geta inside a mine would have been even more dangerous.
5 Arranging flowers
Not only did flowers clash with the atmosphere of the underground coal mines, but they also tended to be used in funerals and other Buddhist ceremonies, thus being associated with graves and temples.
Newcomers to the mines, not knowing the superstitions, would often be cruelly kicked and beaten if they happened to unknowingly put miso soup in their rice.
6 Roasting things at home while workers are entering the mines
It was said that roasting food while one's husband was entering the coal mines would cause him to get injured. Especially avoided items were rice (hoshii) and rice crackers (arare); other roasting activities were not particularly paid much attention one way or the other.
7 Saying "monkey"
The yama people weren't just superstitious about the animal, but also about the word itself. In Japanese, the word for "monkey" (saru) sounds the same as the word "depart" (saru), and was taken to represent the expression, "life departs and vanishes." Also, monkey trainers would often visit the mines, and the police would sometimes capture their monkeys. Thus they reminded the miners of a person who has lost his freedom, and were avoided to some extent, especially by gamblers.
8 Ana and mabu
These terms both basically mean "hole"; ana carries the general meaning, while mabu refers to a hole dug out of a mountain to be used for the purpose of mining minerals. Ana brought the image of a grave hole to mind, and so was avoided when referring to the mine entrance. For the same reason, the term mabu was also generally avoided.
9 Women's times of impurity
This term in Japanese literally means "red impurity." During menstruation or giving birth, the presence of blood was considered to be ceremonially unclean (especially in terms of visiting Shinto shrines, etc.) and as such women were exempted from entering the mines during these periods.
Miners were superstitious about crows cawing in the morning and about bringing flowers inside the coal mine.
10 Impurity of the dead, gnawing on bones
These things were associated with funerals, and as such were considered the highest of all taboos.
Other unfavorable omens included a dog catcher coming to the yama, the smoke coming from the chimney separating into two columns, crows cawing in the morning, and putting miso soup in your rice ("If it's miso you need, you're a bum indeed"). Putting their lives on the line daily in the midst of such dangerous work, it's understandable that the miners would want to avoid anything that might be thought of as unlucky.
11 Bad dreams
Those who worked inside the mines tended not to go to work if they had a bad dream – they would generally fake a headache or a stomachache in order to secure the day off.