Of the three execution grounds of Edo-era Tokyo, the busiest was Koppakatsu. It is said that 100-200,000 criminals were beheaded at Koppakatsu during the Tokugara shogunate (1600-1868). Even if the lower figure is true, that translates to roughly one beheading a day for 268 years.

In those days, it was customary to put the severed heads of criminals on public display to warn the public of the fate that awaited wrongdoers. On his first trip to Tokyo in 1870, W.E. Griffis, an American who had come to Tokyo to advise the Meiji government on educational reforms, saw some heads outside an execution ground as he made his way into the city from Yokohama.

Beheadings were only abolished in 1879, when the new Meiji government was trying to convince the Western powers to end the unequal treaties they had imposed on Japan. Western diplomats had been shocked to learn that the new government still beheaded criminals (depending on the severity of the crime, they also boiled, burned or crucified them) and the new government hoped to curry favour with them by outlawing the practice.

Among those beheaded at the Koppakatsu execution grounds was a notorious murderess called Harada Kinu. O-Kinu, as she became known, was the concubine of a minor daimyo, but was left to fend for herself after the Meiji Restoration deprived him of a living. Casting around for a new benefactor, she became the mistress of a pawnbroker but soon fell in love with a kabuki actor (whose time she had to pay for, as was the custom in those days).

In the winter of 1871, O-Kinu fed rat poison to the pawnbroker, and moved in with the actor. Not long afterwards, she was apprehended by the authorities. She was executed at Koppakatsu the following spring. On the night before she was led to the executioner’s block, she wrote the following haiku: “A storm in the night/ Dawn comes, nothing remains/ A flower’s dream.” The city’s newspapers covered the story of O-Kinu with lurid glee. It was reported that her severed head possessed a weird, unearthly beauty.

The Koppakatsu execution grounds were near Senju, which was the site of one of the six big gates out of Edo. Travellers had to pass through the gate if they wanted to travel to one of the country’s north-eastern provinces. These days, they have to pass through Minami Senju station. Most of the area that the execution grounds used to cover has been swallowed up by the tracks of the Joban and Tsukuba Express lines.

All that remains of the execution grounds is Enmeiji temple, which claims to enshrine the spirits of the people who were beheaded there. In the grounds of the temple is a statue known as the Neck Chop Jizo (kubikiri jizo 首切り地蔵), which was erected to comfort the souls of the dead.

I used to take the Joban line to work when I lived in Matsudo. Passing through Minami Senju, I often wondered about the execution grounds under the railway tracks. I’d look at the commuters around me and wonder if any of them ever gave a thought to the human remains they passed over on their way to work every day.

I once read an article about a man from Cheddar in Somerset who had a DNA test that showed that his family had lived in the area since the Stone Age. I don’t know how much social or geographical mobility there is in Japan, or how many Tokyoites up sticks to go and live in another part of the country, but it seems reasonable to suppose that the majority of the poor souls executed at Koppakatsu have descendants living in Tokyo. I daresay quite a lot of them live, as their forebears did, in Shitamachi, the assortment of older, poorer wards that run north and east from Minami Senju.

Shinto is a religion centred on ancestor worship, but I don’t suppose most commuters think about their ancestors very often – at least not ancestors who died before 1879. They certainly feel the spirits of the recently departed, especially the restless spirits of those who died in suspicious circumstances, whether killed by another, or by their own hand. That’s why landlords struggle to find tenants for the city’s jiko bukken – the euphemistically named ‘incident properties’ where a murder or suicide has taken place.

Well, the past, whether recent or distant, is a mystery. Perhaps that goes some way to explaining Tokyoites’ enduring fascination with true life crime. Once you start thinking about the old execution grounds, knowing that your family have been in Edo since time immemorial, who knows what skeletons you might find in your closet?

The past is a mystery, but so is the present. Leaving Minami Senju, the Joban line used to take me past no end of modern apartment blocks, each as unadorned and unremarkable as the next. Apparently, human beings are social animals, but you could have fooled me. I have scoured those blocks countless times in the hope of seeing some sign of life, but only ever saw endless rows of doors. Who knows what goes on behind them?

If TV viewing figures are anything to go by, their residents are feasting their eyes on some gory spectacle or other. Once the light entertainment programmes are over, and the watershed has been passed, the people of Tokyo like nothing better than to settle down with a saigen dorama 再現ドラマ – the dramatic re-enactment of a true-life crime. The days of the public executioner may be long gone, but a good murder has lost none of its macabre allure.

Enmeiji temple is a short walk from Minami-Senju station at 2-34-5 Minamisenju, Arakawa-ku, Tokyo 116-0003.