Simple idea: Build a wall!

Horio Yoshiharu, the founder of Matsue, established the city around the castle–which even today among multi-story buildings is the highest structure in the city–and the only remaining original castle in the San’in region. It’s a castle build on a hill with a stone wall, which most castles in the San’in region were not (notice which castles aren’t around anymore!).

By wall, I don’t mean a single wall–rather, the moat is lined by a wall, higher and higher levels of the hill have their own walls, and the castle tower itself has a base of stone. They wind around the hill, separating different sections and levels that had different defense and storage purposes back in the Edo era.

Did you know?
The entire walled area can be considered Matsue Castle, though many of the outermost gates have since been demolished. What we would consider Matsue Castle proper is merely the tower, one of several buildings that had special functions. Nor was this the feudal lord’s dwelling place–he lived just south of the castle hill, in close proximity to where government affairs were (and still are) handled. Castles like this were designed as a safe getaway place if he needed to take cover from an attack on the city.

Three wall building methods
The stones used were all taken from Nakaumi (the lake bordering Matsue to the east), and then cut and arranged according to the following methods:

Can you find all three types here?

Besides just making it hard to scale the hill unless you have an army of monkeys, parts of the wall were also designed to give the defending armies the upper hand. For instance, a large square platform called the Katen (firing point) was located along the stairs from the forefront gate. Defending armies could easily shoot at attackers from this point, as the attackers would have little choice but to use the stairs.

The thick brown lines are where there are stone walls.

Speaking of stairs, they were built unevenly so as to make it harder for attackers to run up them. The stairs from the forefront gate at the southeast corner are now a little more conducive to visitors (although still a trek if you try to run up them!), but some stairs, like these on the north side, are still a good challenge if anybody really wanted to try to attack.

It seems to me this quiet set of stairs on the west side has been redone, but they’re still a little too steep to run up them easily.

So… rocks. Walls. That’s great. End of story?
Wrong! What in the world are you supposed to make of this carving?

The answer: sanctioned graffiti!
In some ways, these were the builders’ way of signing their work, or possibly for marking which boulders were to go in which places, as many of the carvings where found along the wall marked below:

Again, the thick brown lines are the stone walls.

They may have also been used to keep track of events and construction associated with the wall, as there is one location marked with “安永八” which most likely marks the eighth year of the An’ei period (1779 a.d.), when part of the wall was reconstructed after heavy rains the previous year had damaged it.

The symbol of a weight in the above example was particularly popular, because it wasn’t the mark of a worker, but of the overlord. It was a family symbol bestowed on the Horio clan from Yoshiharu’s first lord, Toyotomi Hideyoshi (there would be two more clan symbols added later). While samurai clans each had their own crests, family symbols were a little different, as lower ranking families may have them as well. Unfortunately, that’s about the extent of my knowledge about their use, but here are some examples of the common symbols carved on Matsue Castle’s walls:

I find it really funny that someone is using the symbol of onmyouji Abe no Seimei (the star).

You might notice on the map that the wall doesn’t run all the way around the castle hill, but if you were visiting in person, you would notice the forest around the north and west sides of the hill right away, lining the edges of the moat. Some of the individual parts of the forested area had other functional purposes, but the main purpose of the little woods was for defense.
Why go with trees when you can have such a cleverly designed wall? Well, trees are cheaper, and stone walls have a high labor and material cost, and establishing a whole town around your new castle is rather costly, as well as the moving process. In short, they ran out of budget. Thanks to this lack of money, we get to enjoy a number of trees that are hundreds of years old!