I have no idea what's the second kanji supposed to be, first is 御 (I think) and the third is 帳 but the second is something weird.

It could possibly be a very weird version of 開帳...

*edit*

One of the comments in pixiv mentions "御開帳," so I'm guessing it is that.

It's a handwritten abbreviation for 開. 門 and 間 can also be abbreviated in the same way. They're some of the most common of a class of simplified variants called ryakuji (第 is another frequently abbreviated character).

Most ryakuji don't exist in Unicode or common fonts, so they aren't easily reproduced in electronic text. As a result, familiarity with them in online communities tends to be low.

Arcana55 said:

It's a handwritten abbreviation for 開. 門 and 間 can also be abbreviated in the same way. They're some of the most common of a class of simplified variants called ryakuji (第 is another frequently abbreviated character).

Most ryakuji don't exist in Unicode or common fonts, so they aren't easily reproduced in electronic text. As a result, familiarity with them in online communities tends to be low.

What a great way to filter, bully or humiliate people online. TIL.
Thanks to both of you and to Salome of course.

Never heard of Ryakuji before. That's going to make my learning even more fun. orz