Ryukyu Clothing (Ryusou/Uchinaasugai - "Kimono")
PSA: I am not a professional dresser or historian and finding this information is more of a cultural hobby. Please correct me if you see any discrepancies.
From a Ryukyuan-language standpoint, I don't think it's appropriate for Ryukyuan clothing to be called "Kimono" because it isn't Japanese. The general term meant to talk about Okinawan clothing in the Ryukyuan Kingdom context is 琉装 (Ryusou in Japanese/Uchinaasugai ウチナースガイ in Uchinaaguchi). I'm calling it "Kimono" here because it's the most easily understandable. Additionally, this post will not include textiles from the Amami or Ishigaki region and focuses on Uchinaa.
Most Ryukyuan clothing is made for the weather of the region, which can be more humid and hot than Japan. Sadly, if there was record of Ryukyuan clothing before the Kingdom era, it's lost to history. Being a region of trade, a lot of clothing takes inspiration from the many cultures and countries the Ryukyus were in contact with (Southeast Asia, East Asia). Textiles that included Bingata, Kasuri, Silk, or Patterns were for those of upper classes.
I think the most well known style of Ryusou is the one that incorporates a Bingata robe over ウシンチー (Ushinchii). The robes were made of silk and was usually worn by the upperclass citizens in the Ryukyu Kingdom. They tend to have larger sleeves for air. It also tends to fit "loose" since it's very easy to sweat in the region. For men and women formal attire consists of a two-piece outer garment worn over an underwear garment.
ウシンチー Ushinchi
Below is an example of me being dressed in a ウシンチー (Ushinchii) style, which as you can see in this situation the ウシン (Ushin) sash is small. Doesn't always incorporate Kasuri, sometimes it's a solid color. Sometimes it will incorporate other Ryukyuan style clothing.
This is a more formal style of dress but this is an example of one look when they are paired together.
ドゥジン & カカン Duujin and Kakan
There are other clothes for women like one worn by court ladies that are "two pieces" likeドゥジン (Upper piece) and カカン (skirt). They can also have a Bingata robe worn over it. I believe the Kakan is inspired by the Hanfu and Mamianqun.
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ハチマキ Hachimaki
For formal wear for men in upper classes, the clothes tend to be more simple. They wear a ハチマキ (Hachimaki) which is a hat meant to denote your rank. Men also would tend to wear thicker sashes or obi than women.
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芭蕉布 Bashofu
For common people, I don't know what the name for the attire would be but it was made of Bashofu (banana fibre). Now the textile is quite rare and sought after but before the war, it was commonplace to wear and typically worn much shorter than a Japanese kimono (around the shins). It was a relatively breathable fabric and the sleeves are more like open sleeves than what a kimono is like.
(Source)
There are more names, terms, and history that I need to learn but thank you for reading this.