Secrets of Osaka Castle


Written by aki

Osaka Castle is also known as Kinjo

When it comes to sightseeing in Japan, castles are indispensable.

There are many castles in Japan, but one of the most popular is Osaka Castle.

Osaka Castle

It is easy to get to by train, and you can enjoy cherry blossoms and autumn leaves in each of the four seasons.


In fact, there is a secret about Osaka Castle that even Japanese people are totally unaware of.

In this issue, I will introduce four episodes related to Osaka Castle.


1. Osaka Castle’s other name is “Kinjyo”

Osaka Castle is also known as Kinjo(きんじょう).
Kinjo is written in Kanji characters as “錦城” or “金城”.

The kanji “城” means castle.The kanji in “錦” or “金” means gold.

So, the literal translation is “golden castle”.

Osaka Castle is also known as Kinjo

The reason for this alias is that when Osaka Castle is illuminated by the setting sun, the castle glows gold.

Another theory is that Toyotomi Hideyoshi favored “gold,” and people named it Kinjo out of nostalgia.


2. Osaka Castle’s stone walls were transported using kelp!

Osaka Castle's stone walls were transported using kelp!

When building the stone walls of Osaka Castle, they used the “sliminess” of kelp(Kombu in Japanese) to carry large stones.

It is said that the culture of kombu-based dashi took root in Osaka because of the large amount of kombu used.


3. The green color of the roof is actually rust.

The green color of the roof is actually rust.

The beautiful green roof is actually rust.

The roof is made of copper and was originally reddish copper in color.
Over the years, rainwater oxidized it and rusted it, called “green rust,” giving it its present green color.


4. Another Osaka Castle is sleeping underground!

Osaka Castle was first built by Toyotomi Hideyoshi. However, the Osaka Castle built by Toyotomi Hideyoshi was destroyed by fire in a battle called “Osaka Natsu no Jin”.

The present-day Osaka Castle was rebuilt by the Tokugawa Shogunate. At that time, the castle was built on top of a castle that had burned down, so the stone walls built by Hideyoshi are still preserved underground.


Osaka Castle

1-1 Osaka-jo, Chuo-ku, Osaka-shi, Osaka MAP

Short walk from JR Osaka-jo Koen Station / JR/Subway Morinomiya Station / Subway Tanimachi 4-chome Station


What did you think of the secrets of Osaka Castle?
It is very interesting to see the castle from the outside with these tidbits of knowledge!


I have also written a “Himeji Castle” version, so please take a look if you like.



Hello! I live in a place called Shiga, Japan. I'm not very good at English, but I'm writing this blog in the hope that I can convey some of Japan's beautiful places and delicious food to people overseas.