In the darkness, Osaka Castle rises into view. It looks completely different from the lively scene you see during the day. Hidden in its shadows is another face, another story.

Today, many people think of Osaka Castle as Hideyoshi’s luxurious, golden castle. But that image became mainstream surprisingly recently. In 1983, Osaka held the Osaka Castle Expo to celebrate 400 years since the castle’s founding. From that point on, the castle began to emphasize its “glorious Hideyoshi” identity.

So, what identity did it have before that?

After the Meiji Restoration, the vast grounds of Osaka Castle became a major military base. At its center stood the Osaka Artillery Arsenal, the largest weapons factory in all of Asia. During the Sino‑Japanese War, the Russo‑Japanese War, and WWII, weapons and ammunition made here were shipped across the nation by rail and by sea, using the castle’s strategic location.

The factory was also home to Japan’s most advanced metalworking technology at the time. They not only made weapons; they also produced water pipes, bridge structures, and other industrial materials. But it wasn’t a place ordinary citizens visited. Over time, it became a “forbidden zone,” avoided by the public.

Then came August 14, 1945, the day before the war ended.
Osaka suffered its final air raid. More than 80% of the arsenal was destroyed.

Writer Kaikō Ken described the scene after the war: “People discovered a red desert in the heart of Osaka.”

Mountains of shattered steel and concrete. Broken bricks formed a barren wasteland.
People digging through debris to sell scrap metal were nicknamed the “Apache Tribe.”

Because of unexploded bombs, the site was left untouched for about 20 years.
Amid the ruins, the main brick building of the arsenal miraculously survived and gradually came to be seen as a symbol of peace.
Yet in 1981, that building, too, was suddenly demolished.

Newspapers ran headlines asking, “Why was this done out of public view?”

Two years later came the Osaka Castle Expo.

This event not only marked the 400th anniversary but also reshaped the future of Osaka Castle Park. The entire park became a massive pavilion where gardens, plazas, and halls hosted exhibitions and concerts.

At the opening ceremony, the Crown Prince and Princess attended alongside about 9,000 guests from Japan and abroad. Konosuke Matsushita, serving as chairman, proudly declared the start of the “Osaka 21st Century Plan.”

Around this time, JR Osaka Castle Park Station was built. And on the site of the demolished arsenal building, Osaka‑jo Hall was constructed. With that, the city quietly closed the curtain on its military past.

Some of the monuments you pass on your night run may be remnants of that era. If you pause to look closely, they hint that this castle was not only a symbol of glory, but also a hub of war and industry.

Osaka has long been a city of craftsmanship. At its peak, the artillery arsenal employed 60,000 workers. Although Japan lost the war, for many of these workers, the arsenal was a place where they spent their youth. The skills they developed later supported their work as craftsmen and engineers in postwar Japan.

Konosuke Matsushita was one of them. Drawing on his experience in military manufacturing, he eventually built Panasonic, one of Japan’s most iconic companies.

Osaka Castle is surrounded by layers of light and shadow, two intertwined histories.
As you run, think not only of the castle’s daytime brilliance but also the memories hidden in the night.

Once again, Osaka Castle speaks through the rhythm of your footsteps. “RUN RUN LEARN,” a journey through history in motion. At night, the castle invites you into yet another story, one that quietly overlaps with your own path.

*This guide was created based on documents and interviews, and includes some interpretation done by us at ON THE TRIP. Theories differ between experts, so try to find out what really happened on your travels!