Artist's commentary
We got there at just the right time, as they held the walk right after we entered.
An annual pass is ¥4100, by the way, so if you're going to go there more than twice, buying one of those is the way to go.
Apparently, even if you get in via a normal ticket, if you show them the stub on that same day, they'll sell you the annual pass for the difference of ¥2050. If you go there once and you like it, using that method might be a good choice too.