Is Black Swan the copy of a korean movie? I don’t know, but this 3rd opus of 여고괴담 is magical!
The theme of lesbianism that was so strong in the second movie is here only an aside; the movie focuses on the very friendly relationship between the two best students of the school, Jin-sung and So-hee. When So-hee is chosen pour the classical ballet Giselle, the friendship between the two girls turns into a conflict. It is very similar to Black Swan by Darren Aronofsky, with Natalie Portman and Mila Kunis.
We then find the plot used in the Yeogo Goedam movie series: the ghost of the student comes back for revenge. There are some interesting magical effects, including some with mirrors:
But the main effect of the movie is somewhere else.
The title Wishing Stairs refers to a place in the school. The main element of the movie are stairs leading to the entrance of the school. These stairs count 28 steps. Rumor goes that if one goes up the stairs while counting the steps, and strangely counts a 29th step, then one is allowed a wish. In the movie, Jin-sung makes the wish to win the competition. Soon after that, So-hee, her rival and former friend, will have an accident ruining her hopes as a dancer; she eventually commits suicide. Hye-ju, an obese girl secretly in love with So-hee, then makes the wish for So-hee to «come back». Her ghost comes back and takes control of Hye-ju to achieve her vengeance toward Jin-sung.
These stairs with an appearing/disappearing step is very magical. It reminds us of routines by Gaétan Bloom and Christian Chelman, where someone finds out he is immortal because the card he thought-of is the only one missing in the deck. Also with cards, there might be a way to use the Prediction à la Kruskal (cf. page 68 of the book Mnemonica by Juan Tamariz) to support the same idea.
In general terms, this idea with stairs is fairly classical. It is similar to things like «If I walk across seven redheads today, then I’ll do this, or this»; we leave a choice (or the confirmation of a decision, or the will to do an action) to chance.
We could imagine a Copperfieldian version with a special staircase, 100 assistants and the whole circus. But we can also imagine simpler and more modest versions. One I’m thinking of, without having any idea for a solution yet, would use a bracelet ou a pearl necklace. We say that the necklace has 12 pearls. But if, when counting them, a 13rd pearl is counted, then a wish is granted. Christian Chelman has created a completely different effect with a pearl bracelet, «Erzulie’s gift», described in his book Compendium Sortilegionis.
We could also imagine a version with coins: an extra coin will appear each time we count them. Although it has not been used in the same way, this is also the idea behind the 6 bills or 6 cards trick (we remove 3 cards, and there are still 6).
Now it’s up to you to explore these ideas, to change the effects and the objects, but to keep the two main ideas of the movie: Seeing the confirmation of one’s decision/wish in an event actually left to chance, and Having to pay the price, always unexpected and sometimes perverse, after the wish has been granted.