Store-exclusive bonuses are reavelead. 5 store brands would be giving out their exclusive bonuses. All the first edition of the book sold everywhere would have a eroge-theme like reverse cover.
Melonbooks: A3 Tapestry (same picture as the first edition reverse cover with all the girls) + small illustrated cardboard + alternative cover with a short-short story of Rudi on the back of it
Toranoana:
A3 Tapestry (erotic picture of Rudi and Yukine) + short story of Rudi and Yukine.
Tsutaya: Short-story of Yukine with the illustration of Yukine done by
Aoi Nishimata.
Animate: Short-story of Hatsumi
Gamers: Short-story of Hatsumi (different ss from Animate)
Soucrces:
Syosetu
Sneaker official site
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Toranoana bonuses looks the most gorgeous and Melonbooks bonuses offers the most.
Tsutaya bonus would be pretty rare. Animate and Toranoana bonus is dull compared to other 3.