Zori are a type of Japanese-style flip flops. Traditionally, farmers made them during winter using rice straw from their fields. They were meant as footwear for outdoors and pretty much everybody wore them when walking short distances.
Interestingly, they are fairly durable. Remember that in the olden days of Edo, the streets were not paved, so little stones would get stuck in the gaps between the straw and over time create a durable sole. On wood surfaces or even tatami this would be disastrous, hence, they were always taken off before entering a home or temple.
Zori are still quite popular, and nowadays, they are also made from fabric, but this version is meant for indoors. They can be very colorful, and they are very comfortable in summer when it’s too hot for socks or slippers and you still don’t fancy walking barefoot.
Below is a video (in Japanese with subtitles) that teaches the process of making zori from old t-shirts step-by-step. It’s quite a way to go until summer, but it’s good to get a head start.