If you read Ota Gyuichi's Shincho Ko-ki and other sources related to Battle of Nagashino Nobunaga's headquarters was first at Gokurakuji which was true. However, just before the battle began, Nobunaga moved his main army to Chausuyama.
Here is a link with photos of Nobunaga's headquarters at Chausuyama:
Hide has some nice photos of Nobunaga's Chausuyama camp. I have been to the battlefield a couple of times, but never visited the landmarks related to the battle. Hide at the moment is doing yeoman's work on Nagashino. Sublime job in my opinion.
Tenka no tame!