chitose

CQ43 explains the versatility of the box: lid can be used as 干菓子盆, for てんしん or for お白湯. Bottom part for 主菓子 or 炭斗.
古帛紗 is 12 × 12.8, it's smaller. If you use a standard size 古帛紗, it gets quite tight with the 茶杓 and the 茶巾. In that case, my approach in 2026 is to purify the 茶杓, then while holding it put out (or put away) the 古帛紗. It works quite well, and that's how I did it for my 弓道 presentation in 2026.
Developed by 淡々斎's wife for his 60th birthday in 1953. The poem on the lid was:

千歳までかわらぬ　いろの　こはの松　きみが　よばひも　かくこそ　あらなむ
The pine in the garden of color which changes not for a thousand years
May Your life, Too, Be as this.

You pick up the 帛紗 with L (and for cleaning the 茶杓, you pick it up from its R side, like in 貴人薄茶). It's similar to 御所籠 in that regard, and my conjecture is that because you're serving your husband, you want to avoid turning away from him as much as possible.
Even though you have the 古帛紗 protecting the lid, you still hold the bowl from above.
The 茶杓 and 茶碗 come out of the 盆 (and go back in) separately. Similarly odd, the 棗 comes out with L, but goes back in with R.
Just like in 盆略, you clean the 茶杓, move the 棗 to the middle of the 盆, then you ポンポン. (Then close the lid and tuck away the 帛紗.)

The beginning is very nice: Purify the tray, purify the 棗, purify the 茶杓; all in one go. I'd probably put most stress on the 盆, then become more flowing. When you put down the 帛紗, you can directly pick up the 古帛紗, which is also nice.
You can put it already in the room, leaving your 帛紗 on it; then tucking it in at the beginning of the 点前. In that case, so the books say, it's best to also finish in this fashion.
You can do with or without 拝見. If you do, then put 茶杓 and 棗 on the tray; the guest will not pick up the items, but just look at the tray. (This is what my old notes said, the new books say that the guests will 拝見 with their 古帛紗 so that they can also inspect the 盆.) In any case, the 盆 lives outside of their 畳.

Given that this 点前 is now in the books together with 略盆, it's surely a bit of an odd 点前. It has lots of simplifications that we wouldn't see otherwise, mixed with purification logic that comes from higher 点前.
It also sits in an odd place between 平点前 and 茶箱. You can carry the 帛紗 in your belt, or leave it on the 千歳盆 (but tucking it in during the 点前). It would be cleaner, I think in 2025, to treat this as a 茶箱 and have the 帛紗 out during the entire 点前.
- Related to that: The books say that if you start with the 帛紗 on the box, you need to finish like this, too, and vice versa. I think this is a neat time to practise different folding forms to keep things changing as per 棚 logic.
It's the only 点前 where the 薄茶器 is taken out of the box directly as it's being purified. I like this, but it feels mighty abbreviated on one hand, and a bit 盆点 on the other hand (with the 茶器 being cleaned when the 茶碗 is still out of sight). In that spirit, I love how the 3 things that need purifying are purified directly one after the other: 盆・茶器・茶杓. Here I'd make a decrescendo in terms of 捌き-intensity (in 2026).
- The 茶碗 gets cleaned with the 茶巾 after the tea, but that the 茶巾 is not refolded (because the 茶碗 doesn't stay in the room).