Written by: Jin Fujisaki / Published: 2026-01-29
You're deep in focus, working away, when you happen to glance at the cup beside you. And there it is — a tiny speck of dust floating on the surface, somehow having found its way in. Do you "pretend you didn't see it" and drink anyway, or pour it out and refill? That tiny bit of stress chips away at our concentration.
"UENOSUKE SHITANOSUKE," co-developed by Sakae Kasei, Zariganiworks, and TENT, is the answer to this desk-side water dilemma. This isn't just a cup. It's a "hydration capsule" that protects your water and turns the act of drinking into entertainment.
- | Two cups, one set: the "brother cups"
- | Why this shape?
- | The lid becomes a "plate"
- | Who is it for?
- | Summary | A "ritual" for drinking water
- | Related Information
| Two cups, one set: the "brother cups"
image TENT
True to its name, this is a two-piece set: the slightly larger older brother "Uenosuke," and the slightly smaller younger brother "Shitanosuke."
Used separately, they're a beautiful pair of glasses in different sizes. But place Uenosuke on top of Shitanosuke, and they click into place, transforming into a single "transparent capsule."
In this state, you can leave it on your desk for hours without any dust getting in. Because the rim is fully covered, it stays hygienic. With a presence reminiscent of a recovery item from a sci-fi film, just having it there makes you want to drink water.
| Why this shape?
image TENT
This organic form is the product of the almost obsessive craftsmanship of its manufacturer, Sakae Kasei.
- Made of "Tritan": It looks like glass at first glance, but it's actually made of the latest synthetic resin, "Tritan." It has the transparency of glass, yet boasts such durability that it's said it won't break even when dropped from the 10th floor of a building.
- Hand-polished by craftsmen: The pieces aren't simply pulled from the mold and shipped as products. Each one is hand-buffed (polished) by craftsmen, one at a time. That smooth, water-droplet-like finish is born from this painstaking process.
- Function as a lid: When you flip Uenosuke upside down to use it as a lid, it's designed so the rim never touches the table. Hygiene has been considered down to the last detail.
| The lid becomes a "plate"
image TENT
You're working, and you pour water into Shitanosuke to drink. Meanwhile, what becomes of the now-idle Uenosuke?
As it turns out, Uenosuke also functions as a "small plate." Fill it with nuts or chocolate and set it beside you. Water, and a snack. Just having this set transforms a barren desk into an elegant lounge.
When you're done drinking, return it to its capsule form and put it away. The sequence of "opening," "pouring," and "closing" becomes the punctuation of your workday.
| Who is it for?
image TENT
This product is recommended for any worker who cares about their desk environment.
- People who forget to stay hydrated: With a beautiful capsule sitting in front of you, your hand will reach for it without thinking.
- People with cats: Anyone who wants to reduce the risk of their beloved cat drinking from (or knocking over) their glass while they're away from their desk.
- People who are afraid of breaking glass: Whether in households with small children or out camping, you can safely enjoy glass-like beauty.
| Summary | A "ritual" for drinking water
image TENT
So, what did you think?
It's just water — and yet, it's water. Drinking straight from a plastic bottle is fine, but water poured into a beautiful, dedicated vessel somehow tastes different.
Unbreakable, untouched by dust, beautiful. With these transparent brothers on your desk, a little moisture should return to your dry daily routine.
