Developed by Ennōsai, then Zabōsai brought it up again during Covid and made a video about it.

In it, he explains that Ennōsai used a huge ass 長盆 because the 畳 at that time where bigger, and that you're free to use what you think fit. He himself seems to be trying to 好み a smaller sized 長盆, but I haven't seen that yet.

You start with a normal 濃茶, but because you're only serving one person, you scoop 3 times and that's that. No 周り出し, so also no wiping of the rim and, I suppose, during 拝見, no purifying the rim (just like in 天目).

There's still 総礼 with the main bowl for all. After you inquire about the お服, you stand up and go to the 水屋. The first guest continues to enjoy his bowl, cleans it and puts it to his left until further notice.

Zabōsai explains that the 半東 needs to get the timing right to put the tea in just as needed so it remains fragrant.

Take a full ladle and pour half a ladle into each bowl in the order above. 置き柄杓, then blend in the above order, holding the bowls from above.

Take the 盆, turn to face the guests completely, and turn it on the 畳.

The second guest fetches it, puts it outside, takes his bowl inside, and passes on the 盆. Last guest takes his 茶碗 inside, then puts it on his hand. They all start drinking as soon as they have their bowl, no further bowing. After the first sip of the second guess, there'll be the usual chat.

After cleaning the bowl, everyone puts it outside again. The 詰 places his bowl on the 盆 directly. This is the moment when everyone passes down their bowl, where the 詰 gathers them onto the tray.

They take it to the 茶道口, which is still open, and the 半東 will get it. Once the 詰 is back, first and second guests お先に to begin 拝見. (The 数茶碗 are not 拝見ed.)