Akishima Day Trip from Tachikawa: Whale Fossil, Wisteria and History

Akishima, nine minutes from Tachikawa, was sea two million years ago. A whale fossil found by a father and son, an 800-year-old wisteria and an island name.

日本語で読む（Japanese version）

Board the Ome Line at Tachikawa Station. Nishi-Tachikawa, Higashi-Nakagami, Nakagami, and the fourth stop is Akishima (昭島). According to the City of Akishima, it is nine minutes from Akishima Station to Tachikawa Station. About as far as it takes to finish a can of coffee from a vending machine.

Step off the train and look down: on the manhole covers, a whale is swimming. Spouting water, in a sea with thunderheads piled up in the sky. This in a town some 40 kilometres from Tokyo Bay, about 100 metres above sea level.

Two questions arise. Why is there a whale on the manhole covers of a town with no sea? And why does the name of a town with no sea contain the character for “island,” shima (島)? I had always thought of Tachikawa’s neighbour as nothing more than “the residential area west of Tachikawa.” But once I started looking into it, all that came out from under this town’s ground were stories of sea and islands.

Into Akishima: 9 minutes from Tachikawa, and a whale on the manhole cover

Akishima is almost in the middle of Tokyo Metropolis — which stretches far west of the city centre into the Tama area. According to the city’s profile, it borders Tachikawa to the east and north, Fussa to the west, and Hachioji and Hino to the south, and covers 17.34 square kilometres. The land slopes gently from north-west to south-east, down towards the Tama River.

And out of the bank of that Tama River, in the summer of 1961, came a whale.

GSJ Chishitsu News (GSJ Geological News), published by the Geological Survey of Japan at the National Institute of Advanced Industrial Science and Technology, has run a slightly unusual series that reads local geology from manhole covers. Its fourth instalment was Akishima’s whale. The writer asks why a marine mammal is drawn on the manhole covers of a city in hill country, and writes that when you visit Akishima, you notice structures and characters modelled on whales in all sorts of places besides the manholes. There are shops and facilities in the city with “whale” (kujira) in their names — parks, a hospital, pharmacies, a funeral company, car parks, a care home, even a ramen shop. The citizens’ festival, the choir, a road, cookies and manju buns are all whales, too.

An engineer at a national research institute has counted every whale in town. His thoroughness made me laugh a little. The same article says the first whale manhole cover was installed in 1989; at least by then, it suggests, the citizens’ fondness for whales must have taken root.

The city’s own guide lists places where whales can be found: the stained glass at Haijima Station, the manhole covers, a mural in a pocket park in Midori-cho 1-chome, the street lamps on Tsutsujigaoka-dori. There are whales even in the station’s glass. The whales of this town watch travellers from under the ground and from over their heads.

So when, and how, was the whale found? The record of the day of discovery survives in surprising detail.

The summer the Akishima whale was found: 20 August 1961, on the Tama River bank

The City of Akishima’s official page tells the story of the discovery of the Akishima whale in the order of a newspaper report: when, where, who, why.

When: 20 August 1961, just after noon.

Where: on the Tama River floodplain, about 36 metres downstream from pier No. 11 of the JR Hachiko Line’s Tama River railway bridge.

Who: Tajima Masato, then a teacher at Akishima Municipal Tamagawa Elementary School, and his four-year-old son.

Why: father and son had come to the riverbank during the summer holidays to look for fossil shells and fish, and to cook rice in a mess tin over a campfire — hango-suisan, a beloved Japanese outdoor ritual.

Japan’s first almost complete fossil whale skeleton was found by a father and son who had come to cook rice in a mess tin. I read that “why” more than once. In the column for the motive of a historic discovery, it says: cooking rice outdoors.

In those days, the bed of the Tama River looked different from now. According to the city, in the post-war years gravel was dug from the river as material for concrete to build offices and roads, and two-million-year-old strata had been laid bare. Locals called it name: a layer of grains somewhere between sand and clay. Fossil shells and fish were often found there, and many fossil shells came out when the piers of the Hachiko Line bridge were built, too.

Tajima noticed the tip of a fossil poking out of the surface: 10 centimetres long and 3 centimetres wide. Looking around, he saw a line of small holes — signs of fossils sleeping below — running for more than ten metres. According to the city’s summary of the discoverer’s own book, Tajima turned it over in his mind: could this be a dinosaur? No, impossible, given the strata. Too big for an elephant. Then he hid the first fossil under a stone and went home.

The next few days are my favourite part. Reading through encyclopedias told him nothing. He went to the site every day and kept simple notes. On 26 August he consulted a fellow teacher and informed the Board of Education. On 28 August, excavation began, with five teachers and two Board of Education staff.

The next day, the 29th, the man called in to identify the find was Dr Kono, a professor of archaeology at Kunitachi College of Music. The city’s record quotes him: probably the bones of a whale. Judging from the strata, more than a million years old. The teachers who had been digging, it also says, were stunned to hear the word “whale.”

Kunitachi College of Music is now a university in Kashiwa-cho, Tachikawa. As I wrote in the article on Tachikawa’s cultural spots, it grew up in the university town of Kunitachi, where it moved at the end of the Taisho era (1912–1926), and moved to Tachikawa in 1978. So in the summer of 1961, the first person to say “whale” on the Tama River bank came from what would later become a Tachikawa university.

On the 30th, Dr Ozaki of the National Museum of Nature and Science and others arrived with newspaper reporters. The announcement at the press conference was that this was a whale fossil from five to two million years ago, probably a medium-sized baleen whale 15 or 16 metres long, and that so complete a fossil was a first for Japan and rare even worldwide. Television and radio covered it, the mayor and the superintendent of education took the lead, citizens joined in, and the number of hands suddenly grew. Tents went up on the site, and Board of Education staff stayed there overnight.

The dig went on until 3 September. To be able to reconstruct later how the fossil lay, they stretched a grid of level lines every metre and recorded positions as they dug. The fossils were fragile, so they were coated in plaster as they went and carried to an empty classroom at the nearby Municipal Seirin Elementary School.

Then came 4 September. After heavy rain that had been falling since the night before, the excavation site sank beneath the river.

The city counts this as one of the miracles. The fossil was found in the brief moment when part of it lay exposed. Had heavy rain come, it would have been scoured away by the river. If the day of that riverside rice-cooking had been a few weeks later… Thinking about it sends a slight chill down the spine.

Two million years ago, Akishima was sea: 57 years to a new species

In the empty classroom at Seirin Elementary School, the restoration of the fossil took a whole year. The local teachers who had joined the dig formed an “Earth Science Study Group” and worked after school and at weekends. They cleaned off mud and sand, joined broken bones with glue, soaked brittle bones in glue thinned with water and let them dry, and matched up parts from piles of cardboard boxes. The work was finished on 23 August 1962. From 14 to 16 December that year it was shown to the public, and visitors gasped, it is said: it’s big; it’s even bigger than I expected. In the same year, the dig was chosen as one of the “100 selected science and technology achievements of 1961,” as “the excavation of Japan’s first almost complete fossil whale skeleton.”

It was given a name in 1963. Dr Nishiwaki Masaharu of the Whales Research Institute and Dr Ozaki Hiroshi of the National Museum of Nature and Science gave it the informal name “Akishima Kujira,” the Akishima whale. The fossil was kept at the museum’s Shinjuku branch until March 2012, then moved to the Gunma Museum of Natural History, where proper research began.

The research took about four and a half years. The differences between kinds of whale show most clearly in the skull, so the researchers travelled abroad again and again to compare it with whales in museums around the world. The paper was submitted in September 2016, accepted the following March, and published on 1 January 2018 in the English-language journal of the Palaeontological Society of Japan. Its authors were Hasegawa Yoshikazu, honorary director of the Gunma Museum of Natural History, Kimura Toshiyuki, a curator there, and Dr Kohno Naoki of the National Museum of Nature and Science.

The conclusion: the Akishima whale is a previously unknown species in the same genus as the gray whale that lives in the North Pacific today. Its scientific name is Eschrichtius akishimaensis. The city’s page for children explains that akishimaensis means “born in Akishima,” “found in Akishima.” Fifty-seven years after the discovery. From now on, researchers all over the world will say “Akishima” every time they talk about this whale. It is said to be the first fossil species ever found in the gray whale genus.

The fossil was designated the holotype, the single specimen in the world that defines the species — the yardstick against which newly found whale fossils are compared when they are studied. That is why it must be strictly looked after and made available to researchers. The skull that decided it was a new species is on permanent display at the Gunma Museum of Natural History. The head of a whale born in Akishima is serving as a world standard in Gunma.

So why was there a whale in inland Akishima? The geology article’s answer is clear. Beneath the Kanto Plain is a great basin, about 6,000 metres deep at its deepest, and the sea once spread over a wide area that included the Akishima area. Sediment kept pouring into that sea and filled it in, and that is how the Kanto Plain was made. The Akishima whale came from a layer called the Komiya Formation, laid down between about 1.95 and 1.77 million years ago — exactly when the sea was in the middle of being filled in. The City of Akishima writes that two million years ago there was a coastline at Akishima, and the area is thought to have been half land, half sea.

What came out with it tells of the sea of the time: sharks’ teeth, fossil fish and shells. According to the city, when the fossil was dug up, there were fossil barnacles on the shoulder blade — one sign that this was a shallow sea. On land there were Akebono elephants (Stegodon aurorae) and deer.

The city’s guide adds a little trivia about gray whales. A gray whale tips its body far over to the right and scrapes the seabed with the tip of its head to stir up mud, then takes the muddy water into its mouth and strains out only the food with its baleen. Because most individuals lie with their right side down, they are called “right-handed whales.” Their bodies are covered in barnacles, but there are few on the right side of the head — because they sweep the seabed with their faces every day. In the shallows of Akishima two million years ago, too, a large creature may have been looking for its lunch, rubbing its right cheek in the sand. Not so very different, really, from cooking rice on a riverbank.

The Akishima whale in numbers

• 20 August 1961 — the day of discovery. Check the calendar and it was a Sunday: it happened just after noon on a teacher’s day off.
• 4 — the age of one of the discoverers. Among those credited with finding a new species is a child of kindergarten age.
• About 13.5 metres — the length of the fossil. According to the city, about the size of the Great Buddha of Kamakura (including its pedestal). The city’s guide to historic-site walks gives about 16 metres, so the whale stretches and shrinks a little depending on the document.
• 57 years — from discovery to publication as a new species.
• 2 — the number of throat grooves on a gray whale. Blue whales, which gulp huge amounts of water, have many more.
• 65th anniversary — 2026. The commemorative exhibition at the local history room, showing the actual fossils of the whole skeleton, runs until 24 October.

A wayfarer’s quiz

To what does the City of Akishima compare the size of the Akishima whale fossil (about 13.5 metres)?

1. The height up to Tokyo Tower’s main observatory (B) The Great Buddha of Kamakura (including its pedestal) (C) One carriage of a shinkansen bullet train

The answer is near the end of this article.

The whale carried the name “Akishima” around the world; that much is fine. But where did the name “Akishima” itself come from? I still could not explain why a city without a sea has the character for “island” in its name.