Now, why was this strange medicine ‘toad’s oil’ created in the Edo period in Japan, with its bullshit medicinal properties from toad’s sweat, etc.?
Research into the origins of ‘toad oil’ leads to two traditions.
The first of these traditions. The Osaka War, which took place at the beginning of the 17th century (1614-1615・Just before the Edo period). It followed the fall of the regime of Toyotomi Hideyoshi on his death. The battle fought against the rising Tokugawa Ieyasu was one of the biggest in Japan, dividing the country in two.
The battle, which ended with a 250,000-strong force and more than 20,000 dead, ended with the destruction of the Toyotomi family, but the ravages of the war are said to have been disastrous.
At this time, there was one monk who served under the Tokugawa forces.
His name was Koyo, and he was a high priest of Chisokuin-Chuzenji Temple on Mount Tsukuba.
He was a monk, but took part in the war? Perhaps his role was that of a military doctor. When he arrived at the battlefield, he treated the soldiers who were moaning and suffering here and there with his ointments, regardless of whether they were friend or foe.
The ointment he used was so effective that the soldiers who were treated reportedly recovered one after another. It is thought that this is where the legend spread that the ointment on Mount Tsukuba had the effect of the gods and Buddha. There is also a tradition that Koyo’s face resembled a toad.
There is no historical record of Koyo’s participation in the Tokugawa forces. There is also research that suggests that the ointment used on the battlefield was ‘horse oil’, and it is likely that this kind of folklore was actively used in the later ‘toad oil sales’.
（horse oil / 馬油 Originating in ancient China, an ointment with horse fat as an ingredient.）
The fact that the word ‘陣中 / jinchu’ (in battle) is printed on the containers of ‘toad oil’ sold today is a reflection of this folklore.
Now, another tradition is 130 years after the aforementioned story, in the mid-Edo period. The days of warfare were a thing of the past and society was in the midst of an era of stability and economic activity.
The name of the main character in this story is ‘Hyosuke Nagai’ , from Niibaru village, Tsukuba County.
He was born the son of a peasant but was lazy from a young age. He abandoned a simple life and went to Edo (now Tokyo).
However, when he got to town, he was a simpleton and didn’t work hard, so he quickly fell into poverty and had no money to eat.
He lamented his own inadequacies and decided to at least look out over the world from the top of Mount Tsukuba in his home town before he died, so he made the journey up to Mount Nyotai (a peak of Mount Tsukuba).
However, as the sun was setting, a giant toad was waiting for Hyosuke on the mountain path just before the summit.
Hyosuke had climbed up the mountain determined to die, but the size of the toad, which was even taller than he was, made him fearfully join his hands in chanting “Namusan！”, but it was a huge strange rock protruding from the side of the road…
（Namusan / 南無三 Buddhist wish phrases.）
Toadstones（Gama-ishi） on Mt Tsukuba.
Hyosuke collapses on the spot and falls into a deep sleep, exhausted in body and soul. Then, in his dream, a large toad appeared and admonished Hyosuke to change his life and live sincerely.
After waking up from his dream, Hyosuke spent seven days meditating on Mount Tsukuba. He then came up with the idea of spreading the local special medicine ‘toad’s oil’ throughout the country as his livelihood.
He returned to Edo (present-day Tokyo) to learn how to sell toad’s oil, and with the help of a speech he invented himself, he became a well-known seller and decorated his hometown with his name…
This is a folklore that tells the story of the founder of the ‘toad oil peddler’, who was probably also a real person, “Nagai Hyosuke”. However, the content of the folklore is probably a fabrication.
However, even after 400 years, Toad’s Oil is still being produced and sold, and is a representative souvenir of Tsukuba. The oral performance of the ‘toad oil peddler’ invented and established by Hyosuke has also been handed down to the present day and is recognised as an ‘Intangible folk cultural asset recognised by Tsukuba City’.
The cultural relics and customs produced by the people have passed through time and are still reverberating in the present day.
One final word…
「Toad oil」has no medicinal properties, but there are secretion holes behind the prominent eyes, from the ears to the shoulders, called ear glands, from which the fluid extracted has analgesic and anaesthetic properties. The fluid extracted from these glands has analgesic and anaesthetic properties and has been used as a form of Chinese medicine since ancient times.
The fluid produced by the ear glands can be a very potent alkaloid toxin, depending on the species of frog, and the ancients must have known it from experience as a creature with both good and bad effects…
Caution.
Some toads and frogs are intensely poisonous. Some can be fatal just by touching them, so do not touch them easily.
‘Dendrobatidae’ with the strongest level of venom.