This is a creepy station, green filters notwithstanding. The article repeats this statement that I've seen elsewhere and always found pretty questionable - that 800 people have died on Tanigawa. I've no idea where this data comes from but it seems very unlikely. If you just want to get to the top by the simplest route then it's a non-technical day hike up a not-very-high mountain. It's also a multi-pitch rock climbing area but I'd struggle to imagine that 800 rock climbers have killed themselves there over the past 100 or so years.

Wikipedia also says the same thing, both in English and in Japanese, and in both languages uses this report[1] as the source. This in turn sources a medical journal and a report by a mountaineering club. I don't know Japanese and can't really check whether these are reliable sources that actually exist. Essentially what this report says is that after WWII, particularly in the late 50s and the 60s, there were lots of climbers and unsafe routes, causing a large number of fatalaties. Afterwards there's a sharp decrease, though still pretty significant numbers.

[1]: https://soka-yamanokai.com/study/study18.html

I believe the number is correct. The source from the government: https://www.mlit.go.jp/tagengo-db/common/001556845.pdf

I assume you've never been there. 一ノ倉沢 is really impressive and dangerous.