Loved the vibe, as you approach and also take steps into the tunnel. Worth the short detour if you're hiking around Utsunoya Pass. Constructed in 1876, this was the first tunnel in Japan that required payment of a toll for passage.
Great place but only worth it if you can drive there or plan to hike a lot. Half the lights were out in the tunnel which made it a bit creepy if going alone.
If you drive, there is only parking on the Shizuoka side and it's hard to find. Go up a small road that seems for walking only, but actually has 3-4 spots for parking.
