TsukkiYama

TsukkiYama is the slash ship between Tsukishima Kei and Yamaguchi Tadashi from the Haikyu!! fandom.

Canon
Tsukishima and Yamaguchi are both first years and members of the Karasuno High School volleyball team. The two first met when they were younger, Tsukishima standing up to those who were bullying Yamaguchi. They later met when joining a volleyball team during junior high, and their friendship developed from there.

Yamaguchi refers to Tsukishima as "Tsukki," hence their ship name. However, it's known that Yamaguchi used to call Tsukishima "Kei-kun" when they were children. The two have a very close bond and are in the same class as well. It is noted that Yamaguchi is also close with Tsukishima's older brother, Akiteru, by his first name. They are also seen eating lunch together on multiple occasions.

Though Yamaguchi usually just follows Tsukishima seems annoyed with him, Yamaguchi sometimes snaps at him when he is not taking things seriously. For example, in the Tokyo Expedition Arc, Yamaguchi and him have a short argument, which ends in Tsukishima asking when Yamaguchi "became so cool."

In Chapter 289 they successfully pull off a "Serve and Block", which was a key moment in their relationship. They both high five after their victorious combo, Tsukishima genuinely smiling while doing so. Their friendship remained steady since then.

Fanon
TsukkiYama is the fifth most popular ship in the fandom and the most written ship for both Tsukishima and Yamaguchi.

Fandom
FAN FICTION

Trivia

 * When Yamaguchi's voice actor was asked what type of person Yamaguchi is, they replied with "they love Tsukki very much".
 * There was a supposed interview with the author of Haikyuu!! going around where they confirmed Tsukishima and Yamaguchi have been dating since junior high, however, that interview was proven to be fake.
 * The two met when they were younger after Tsukishima stood up for Yamaguchi when he was being bullied. When they met later at a junior volleyball club, the latter thanks Tsukishima for rescuing him, however, Tsukishima did not remember this incident.