A large tunnel, for a small island anyway, with several doors set into the sides. There are labels on the doors, but they are all in Japanese.

It’s 1854.  Commodore Matthew Perry has just sailed his black ships into Tokyo bay and forced the Tokugawa Shogunate to open Japan to foreign trade for the first time in more than 200 years.  The sudden appearance of large, modern warships on Japanese shores served as a wake up call and made it clear that Japan couldn’t ignore the march of technology anymore.  Of course, Japan in the late Edo period was not in some kind of dark age, completely cut off from the outside world.  The Dutch had been bringing news, books, ideas, and stories of the outside world into Nagasaki Prefecture the entire time the country was closed. So in spite of the country’s relative isolation, the Japanese government knew what was going on in outside the world.  In fact, I have heard it said that, when Commodore Perry finally met with the Shogun’s representatives, they asked about the recent war the U.S. fought against Mexico.  To the Japanese at the time, though, all of this was so far away. But with the U.S. demanding trade and the British, French, and others waiting in line behind them, it was becoming clear that Japan needed a much stronger navy.  At first, this meant buying used ships from other naval powers, but that was just a starting point.  In 1865, French naval engineer François Léonce Verny was hired by the Tokugawa Shogunate to build two modern military shipyards – the first of these would transform a small fishing village on Tokyo Bay called Yokosuka into a naval powerhouse.

The modern city of Yokosuka as seen from the old battery on Sarushima.

Through out the Edo Period, Yokosuka and the surrounding area was under the direct control of the Tokugawa Clan and the Shogun directly, who had built a few small fortifications control watch traffic in and out of Tokyo Bay, inspecting cargo, and ensuring that no foreign ships or illegal goods entered the country.  Of course, this didn’t stop Commodore Perry and his fleet – a fact not lost on the Shogun and his advisers.  That is why they hired Verny and he got right to work, building dry-docks, repair facilities, and iron works, and even launching the Yokosuka-maru, the shipyard’s first locally produced steam ship, in 1866. This also resulted in the expansion of defensive fortifications into modern coastal artillery batteries.  Following the fall of the Shogunate, the newly formed Imperial Japanese Navy took over the Yokosuka Shipyard in 1871, keeping Verny and the other French engineers on until 1878 while they trained the Japanese engineers who would continue their work.  Over time, the Yokosuka Shipyard became the Yokosuka Naval Arsenal which served as the backbone of the larger Yokosuka Naval District. As the shipyard and port facilities were expanded and additional sites were built and consolidated, Yokosuka became the first of four major naval districts in Japan due to its size and close proximity to the capital in Tokyo.

Battleship Mikasa stands on the waterfront, as seen from the ferry to Sarushima.

Some of the Imperial Japanese Navy’s most impressive and important ships were built and berthed in Yokosuka.   Japan’s first submarines, purchased from the U.S., were brought to Yokosuka,  Japan’s first domestically produced battleship, the Satsuma, was built in the Yokosuka dry docks.  Several of the battleships and carriers Japan used in WWII were built and maintained in Yokosuka.  Like carrier Shikoku and battleship Yamashiro.  Technical schools and research stations were established throughout the Yokosuka Naval District and Eventually and Air Technical Arsenal was established to design new naval aircraft for the Japanese.  Throughout the Imperial era, and right up until Japan’s formal surrender at the end of WWII, Yokosuka maintained its position as the most important naval headquarters in the country.  But, the end did eventually come.  The Naval Arsenal and shipyard were taken over post war by the U.S. Navy, who still use the original dry docks designed by Verny in the 1800s.   In fact, what little still exists of the original Yokosuka Naval Arsenal are mostly on the current American Fleet Activities Yokosuka navy base, where several sites, like the dry docks and headquarters buildings, are still in use.  Even so, many of the bunkers are walled off and off limits, – both on base and off.  This is probably the biggest difference between Yokosuka and the other formal Naval Districts from this time period.  While places like Kure and Nagasaki own their naval heritage and seem proud to show it off to the public, Yokosuka has hidden much of it away, leaving only a few traces of what once was.

The path through the former barracks, carved into the stone of the small island. Today, a raised wooden walkway leads past the fenced, locked structures.

However, there are a couple places that remains of the old Naval Arsenal can still be found.  The best known of these is probably Sarushima, or Monkey Island.  This small island is located a short ferry ride from the battleship Mikasa park and contains the mostly preserved ruins of the old Meiji Period defensive gun battery that once inhabited the island.  It also boasts that it is the only island in Tokyo Bay that hasn’t been extensively altered, expanded, or otherwise changed to make it inhabitable.  The island had been used as a small fortification by the Tokugawa Shogunate for much of the Edo Period, but when the Yokosuka Naval Arsenal was established, the island’s defenses were expanded into a modern shore based artillery battery to protect the approaches to Tokyo from hostile ships.  From 1881 until the Great Kanto Earthquake in 1923, the shore battery occupied the entire island with further support buildings on shore nearby.  After the earthquake, however, many of the gun emplacements were damaged, and as technology marched on, they were not repaired.  Rather, the island was converted into a smaller anti-aircraft battery, which was abandoned after the war.  Shortly after the U.S. Navy took over the area, the city started using the island as a marine park, which it still is today.

Sarushima, or Monkey Island. It is said that, during the Kamakura Period, a monk was traveling across Tokyo Bay on a boat when he was suddenly caught up in a storm. which wrecked his boat and tossed him into the sea. When he woke up on the beach, he was certain monkeys had some from the island and saved him, in spite of the fact that no monkeys have ever lived on the island.

So, a few weeks ago, I headed over to Yokosuka, hopped on a boat, and had a look for myself.  In all honesty, from a historical standpoint, it was a little disappointing.  The island itself is a cool place to walk around, appreciate the view of Tokyo Bay, and enjoy a little hiking, BBQ, and nature.  But all of the old buildings and structures are locked and sealed.  Most of the gun emplacements are poorly preserved with just the concrete circle marking where they once stood, with many of the structures around them erased and no other markers indicating what was there.  One emplacement even had a hiking path carved through it.  The observatory at the island’s highest point is chained shut and cut off from visitors.  Meanwhile, there are cones, plastic gates, and caution tape everywhere, almost as if someone considered preserving the remains as a proper museum, but then just couldn’t be bothered.  When you consider the fact that the battery had been reduced by the time of WWII war, and the fact that there are far better sites preserved elsewhere, it hardly seems worth the 1,500 yen for the ferry if you are going to the island for the gun battery.  If you want to see better preserved gun batteries in Yokosuka that were in use during the war, I suggest taking the bus to Kannonzaki Park and hiking up the mountain to see the remains of the old fortress there.  But that is another article for another day.

the path toward the main tunnel,

If you are in the area and have a day to kill, Sarushima is a nice place to visit.  But at 1,500 yen per person just to get there, if you are serious about history, it may not be worth the cost.