The Hokkaido shinkansen is pretty crazy. It's basically just tunnels.
All this is just going to be a tunnel
Mapping in progress construction from google maps is fun.
First one was Watari Tunnel (渡島トンネル).
Here's Nifuku Tunnel (二股トンネル), Bifuka Tunnel (碧雲トンネル), Notaguchi Tunnel (野田追トンネル) and after Yakumo Tateishi Tunnel (立岩トンネル).
Makomanai Tunnel (幌内トンネル), Toyono Tunnel (豊野トンネル) and Kunimatsu Tunnel (国縫トンネル).
After Oshamambe there's Uchiu Tunnel (内浦トンネル), Konbu Tunnel (昆布トンネル), Miyada Tunnel (宮田トンネル) and Niseko Tunnel (ニセコトンネル)
Also I'm a retard, the spots I labeled as ventilation or exploration shafts are entry points for various sections of the tunnel.
Also also, the names might be wrong cuz LLMs and all that.
Cool videos on the progress
Drone shots of various viaducts:
https://www.youtube.com/watch?v=qJAa5_Q5Myk
Sapporo construction progress and explainer from JR Hokkaido:
https://www.youtube.com/watch?v=wBhlqHgQNPM
Remaining are Asari Tunnel (朝里トンネル), which got just finished digging in November so one exit isn't even on Google Maps and Sapporo Tunnel (札幌トンネル) which has the least progress done and I can only find one tunnel entry point and one section entry point