• About this legend: "ベートーベンの怪 "The Beethoven Mystery" - is Another one of the famous "Seven School mysteries" (学校の七不思議) Gakkō-no-Nanafushigi handed down around japan.
I can say with confidence that most schools globally have the same portraits of famous classical musicians decorating the music rooms walls you know the ones i'm sure:
However in classrooms across Japan, its a fairly common rumour that if you visit the music room at night, the eyes of the portraits lining the classroom walls will begin to glow red, their eyes will follow you around or the faces will change expression when you arent looking...
Occasionally, the spirits are also said to play the pianos when nobody is around as well, if you hear it whilst wandering the school at night, its said to be an omen that something bad will happen.
'Ludwig von Beethoven' isn't the only "music room" ghost of course (though he does seem to be the most common.) Ludwig's expression (& somewhat wild hair) is often said to read as angry or judgmental to students. (Especially those that might be performing his music poorly!) - Mozart, Bach and many others are featured too. (I'd imagine 'the exact 'haunted painting' changes from student to student.)
I suppose when you're young, there's an unspoken subconscious pressure: an audience to be found in so many pictures of famous people hung on the walls, could they be listening? [well ironically, probably not Beethoven, as he was definitely deaf by the end of his career. 😂]
in Pop culture: interestingly, the pop culture musician of choice seems to lean towards Mozart: Luigis mansion has 3 different pianist spirits. 'Mr Passion' from Mother 3 is also a direct reference to this legend & The much more recent game, "ghost wire" features Mozarts ghost as the games only jumpscare as well.
Down a similar vein of ghost story, there are plenty of ghostly paintings in the Arts and crafts rooms left by now deceased students that might harbour a grudge... Of course, the trope of 'moving paintings' isn't uncommon at all either, its a popular subject in video games, horror & in entertainment in general as well.
-Anyway. I don't really have much more to say about this one, its certainly a fun bit of modern child-lore if nothing else!
..or. IS IT!? ---Dun dun dun dun!!