Kochiya sanae uses a wooden wand that is markedly different from a gohei. Despite this, the majority of posts have it tagged as a gohei. The oonusa tag exists, and to my knowledge, it's the best fit despite the wikipedia pictures being very different.
There's at least 70 pages of images with Sanae and not Reimu that are tagged "gohei" and not "oonusa". Bulk tag updates exist, but I don't know the syntax for them. Is it possible to do something like:
kochiya_sanae gohei -hakurei_reimu -oonusa -> -gohei oonusa
or is this only possible with tag scripts? 70 pages is a bit much for a tag script.
There are a handful of images where Sanae is actually holding a gohei, e.g. post #1758200, but there are far fewer of these than where she's using her oonusa.
