As the volcano's activity isn't explosive, and there's a whole hot spring business around it, humans have been trying to tame Mount Hakone, as evidenced by the many consolidation structures seen at Ôwakudani.
These continue down the valley to contain landslides which could happen if things get more intense. Nonetheless, occasionally, a gas vent juts out, placing a distinctly natural form amongst the organised, man-made network of walls.
The yellow deposits are typically sulphur from a very pungent gas. Depending on the direction of the wind, the smell in some locations on the summit can be quite literally breathtaking.
The views, meanwhile, are figuratively breathtaking, from the striking contrasts in vegetation in the foreground to Lake Ashi and the outer mountain range of the Hakone caldera in the background.
And, of course, it is possible to see Mount Fuji from Ôwakudani. Terms and conditions apply, as always, but what little I could see on that morning gives a sense of scale to the great mountain. However, later that day, we would be treated to a much clearer view of Fuji-san.