This is Atami castle. (Again, all images are clickable through for mostly higher-resolution versions.)
It's twentieth-century, but built to resemble an Edo-period castle. (Japan has few old buildings, due to a combination of having built in flammable materials, non-earthquake-proof construction, and heavy bombing during the War (with the notable exception of Kyoto, the "city of ten thousand shrines", which was spared).)
As I suspect most of my readers already know, top-quality Japanese swords have a worldwide reputation; they're capable of chopping a European sword in two like a knife going through butter. A Japanese swordsmith will fold the metal of the edge over, hammer it back to its previous length, then repeat that process over and over again, until the edge has got something like four million layers of metal in it—but only the edge. If the whole blade were constructed like this, it would be as brittle as glass. That's the trick that the Japanese swordsmiths mastered, which the European ones never did. If you look closely, you can see a wavy pattern where the two parts of the blade join.
My interest in Japanese weapons was not limited to swords. I recently reread Noel Perrin's Giving Up The Gun: Japan's Reversion to the Sword 1545–1879, which I first read in 2004 after reading a fascinating post on the subject on rec.arts.sf.science;* to cut a long (and surprisingly entertaining†) story short, Japan spent a century flirting with the gun, but ultimately decided it was not an honourable weapon, and turned its back on the weapon. Consequently, I was fascinated by these matchlocks and flintlocks from that brief period of Japanese gunmanship:
* Which I'd link to, but Google's mismanagement of the Dejanews archive has rendered it unsearchable. If anyone wants me to, I'm happy to post it in a comment here.
† For example:
...an Oriental version of Kleenex, a product the Japanese were making in bulk at least three centuries before Americans suppose themselves to have invented this useful item. They even exported it. An Englishman named Peter Mundy happened to be in Macao, on the China coast, in 1637, and was much impressed when he saw some Osaka merchants' representatives using it.
'Some few Japoneses wee saw in this Citty,' Mundy later wrote. 'They blow their Noses with a certaine sofft and tough kind of paper which they carry aboutt them in small peeces, which having used, they Fling away as a Fillythy thing, keeping handkerchiefes of lynnen to wype their Faces.' Natural Mundy was impressed. In England, at the time, most people used their sleeves.
This is an interesting take on the concept of wide-dispersed fire:
I'll finish off this blog post with a selection of pictures from the museum of optical illusions, also in the castle: