Kysa Zerego at the time she was selected to became the next V'ei'ka, her famous purple Ts'shúkí can be seen atop her white Kúshózí
The Ts'shúkí (pronounced Ts-shoo-kee) was an Ingzan garment worn by men and women of all social classes (apart from the poorest of the poor, who couldn't afford them). It was an ankle-length gown (though some were longer, and trailed along the floor) which was made of cloth and was worn over clothes like a dress, trousers and shirt (called Kúshózí when being worn under a Ts'shúkí) or another gown, nearly all Ts'shúkís usually had a Dókyún, a fabric belt which could be tied to stop the Ts'shúkí from flapping loosely whilst walking, though this could be removed.
Many early Ts'shúkís were basic colors like red, yellow, blue, green and black whilst the earliest of Ts'shúkí were all white, being made before dyes were invented. After about a century the Ingza decided basic colors were a bit old and their golden era had ended so they started mixing dyes together to produce new colors like orange, purple, brown and so on.
Eventually white was worn only by the dead as it represented purity of the soul in the afterlife and it became taboo for a living person to wear a white Ts'shúkí as it was considered disrespectful to souls of the departed (however it wasn't taboo for priests to where white Ts'shúkí), because they helped send the dead to V'ei'ka.
As a white Ts'shúkí represented purity of the soul people like murderers, rapists etc weren't buried in a white Ts'shúkí when they died as it was believed their souls was impure and therefore weren't allowed to go to heaven, this was why many Ingzan ghost stories had ghosts in non-white Ts'shúkís, to be buried in a non-white Ts'shúkí was something nearly all Ingzans feared.
Some Ingzan ghosts in the Ts'shúkí they wore when they were alive, even if they were buried in a white Ts'shúkí. An example of one of these types of ghost wsa Kysa Zerego, who as a V'ei'ka was buried in a white Ts'shúkí, yet her living world-bound ghost returned in her famous purple one. However her angel wore the white Ts'shúkí she was buried in.
Some Ts'shúkí represented a person's religious duties or job, like the Temple of V'ei'ka Guardian Ts'shúkí, an elaboratly decorated black Ts'shúkí worn by Temple of V'ei'ka Guardians.
Yóshá Ásáshó wearing a Temple of V'ei'ka Guardian Ts'shúkí
Whilst most Ts'shúkís were just color, some were elaborately designed with pictures of birds, flowers and other flora and fauna. These elaborate Ts'shúkí were usually only worn by upper-class members as they were very expensive due to the labor and time involved in making them by hand.
The Ts'shúkí was one of the signature garments of the Ingza, along with Kúshózí, shirt and trousers worn under a Ts'shúkí. When the Ingza opened relations with the Galactic Federation of Sentient Species and Ingzans began to immigrate to Coruscant and other worlds they brough their clothes with them, Ingzan clothing began to catch on with some of their extra-galactic cousins, humans from Coruscant and other similar worlds immigrated to the Ingza system and picked up the native culture, wearing Ingzan clothes, speaking the Ingzan language, eating Ingzan food and so on.
One of the most famous Ts'shúkís of all time was a purple one which had been worn by living goddess Kysa Zerego most of her life, after Kysa's death her Ts'shúkí went into a history museum.
To the lower-classes Ts'shúkís were special, and were treated very carefully, as it was a sign that they respected and honored their signature garments. However for the upper-classes the Ts'shúkí was standard wear, some upper-class members wore their Ts'shúkís for most things they did.
The Ts'shúkí evolved from the Gírzán, a type of cloak. The inventor of the Ts'shúkí noticed how the Gírzán flapped in the wind quite a bit and decided to add sleeves and a belt to it so it would stay somewhat still and make it so it could go all the way around someone like a coat, he took a Gírzán, added some extra bits to it so it wrapped around someone, added a fabric belt (Dókyún) which could be tied to stop the Ts'shúkí from flapping so much and some sleeves.