Shizukasa

Tsukashizu is the het ship between Tsukasa Tenma and Shizuku Hinomori from the Project SEKAI fandom.

Canon
Tsukasa and Shizuku are second-year high school students, with Tsukasa attending Kamiyama High School and Shizuku attending Miyamasuzaka Girls Academy. Tsukasa is a member of the theatre troupe Wonderlands x Showtime, and Shizuku is a part of the idol group MORE MORE JUMP! (formerly a member of Cheerful*Days). They were acquaintances in childhood, with their younger sisters Saki and Shiho being best friends. Tsukasa and Shizuku were also friends, just not as close as their siblings. They used to play in the park together.

Tsukasa and Shizuku have some parallels in their characters. They are both the oldest sibling who cares a lot and dotes on their younger sister, only Saki unabashedly publicly cares for Tsukasa and Shiho is much more embarrassed by Shizuku's antics. They both also take up a "leader" role to some degree in their groups, with Tsukasa literally being his troupe's leader and Shizuku taking on a mentor role for Minori.

They both also tend to be the member of their group the most in the spotlight. For Tsukasa, this is naturally due to his slightly arrogant and outgoing personality, and tendency to cast himself as the lead role in all his shows. For Shizuku, this is due to her clout and fame as a former idol and model, as well as her beauty. They also tend to be forgetful, oblivious, and slightly ditzy.

Fanon
Tsukashizu is a rarepair in the Project SEKAI fandom, rivaled by RuiKasa, Emukasa, and Nenekasa for Tsukasa and Shizuairi, Minoshizu, and Shizuharu. Although the two are childhood friends, they don't interact much in the game. Tsukasa and Shizuku are also often shipped with all of the members from their respective units, Polyshow and Polyjump.

Some believe that Tsukasa should only be shipped with a male (most notably Rui Kamishiro) and Shizuku with a female (most notably Airi Momoi. This does not stop Tsukashizu fans from shipping them though.

Fandom
FAN FICTION

Trivia
My Sister is the Cutest in the World".
 * They are both the oldest child in their families.
 * Their Kizuna Ranks can be translated to: "Friends Playing in the Park", "I'm a Firm Sister and Brother!", and "
 * It's also notable that most original characters in Project SEKAI don't have Kizuna Ranks outside of the VIRTUAL SINGERS and their own units, but they might have a few others: Tsukasa has the Leo/need members and Toya (along with Shizuku), and Shizuku has the Leo/need members and Mafuyu (along with Tsukasa).