Matsuya's Official X Teased a 'Mystery Cup' — Its True Identity Is Soy Milk Pudding

On the afternoon of July 16, Matsuya’s official X account revealed that the container it had deliberately left labeled a “mystery cup” in a taste-test report two days earlier actually contained Soy Milk Pudding. The post read, “The true identity of the mystery cup is ‘Soy Milk Pudding,’” and also disclosed that it is on sale at all locations except Okinawa.

The “Mystery Cup,” Revealed Two Days Later

It started with a post on the night of July 14. Matsuya’s official account shared a photo of a taste test of the Twice-cooked Pork Set Meal, which had gone on sale that same day, and closed the post with a tease: “Wait, what’s that mystery cup in the background…?” — deliberately leaving the container at the back of the table unexplained. About 41 hours later, sometime after 1 p.m. on July 16, the official account quoted its earlier post to answer, “The true identity of the mystery cup is ‘Soy Milk Pudding.’” The reveal was staged across two separate posts — one hint, one answer — building suspense along the way.

Both the Twice-cooked Pork Set Meal and the Soy Milk Pudding are newcomers that launched together on July 14. Their positioning differs, though: on Matsuya’s official website menu, the Twice-cooked Pork Set Meal is listed as a limited-time item, while the Soy Milk Pudding is not in the limited-time lineup — it’s treated as a regular side menu item.

A 180-Yen Side Menu Item Topped with Kinako and Kuromitsu

The released photo clearly shows the contents of the Soy Milk Pudding. It’s a Japanese-style sweet: a smooth white pudding in a cup, generously dusted with kinako soybean flour and drizzled with kuromitsu black sugar syrup. Even the spoonful lifted for the shot shows the pudding, kinako, and kuromitsu clinging together in layers. In the lower right of the photo, Matsuya’s official mascots, Macky & Yakky, give a thumbs-up with smiling faces to promote the new sweet.

The container’s lid carries the English words “SOY MILK PUDDING” alongside the Matsuya logo, along with the copy lines “Your privilege for five minutes after the meal.” and “Melting, gentle sweetness.”

Priced at 180 yen, it falls in the same price range as other side menu items such as Grilled Sausage & Egg. It’s positioned as a sweet you can easily add on to cap off a meal.

From Announcement to Sale to Reveal

Both the Soy Milk Pudding and the Twice-cooked Pork Set Meal were first announced in an official notice dated July 9, and they actually appeared in stores and on the menu five days later, on July 14. From the initial announcement through the actual sale, the “mystery” posed in the taste-test photo, and now this reveal, the official account has kept the topic going in stages.

It’s worth noting that a same-named item, “Soy Milk Pudding” (written in katakana as プリン), was previously trialed at select stores, but that listing has already ended. It is a different product from today’s “Soy Milk Pudding” (written in hiragana as ぷりん), which is now rolled out nationwide as a regular menu item.