Used in February exclusively at 今日庵, invented by 玄々斎 for a 6-mat room that's in 逆勝手.
If you look at the 手前, it is actually very suited to do it in 逆勝手!
Basically: Because the 釜 sits closer to the 手前座, everything focuses around that corner. So the 炭斗 lives near that corner, the 釜 goes out there; and all the purification is also focused around it. Also, becuase you don't have a 灰器, the 手前 is actually quite simple and beautiful!
In 池庵, I am building what I punnily call a 誇大炉: It still fits the outer dimensions of a normal 炉 (that is, 42.5 ⨉ 42.5 cm), but the 炉壇 and 炉縁 are much thinner. Together with using 風炉 五徳・釜・炭, it gives the impression of a true 大炉.
本勝手 手前
It's a bit of a conjecture, mixing normal 逆勝手 and 大炉, but it works quite smoothly, I think.
Preparation: The 釜 is in the corner closest to where you'll do 点前; and the 炭斗 is packed for 逆勝手 (香合 to the L, 羽 and 火箸 to the R). In 大炉, the 灰匙 and the moist ash are already in the 炉! The 釜敷 goes into the 着物 as it would in 本勝手 winter.
Entering: You come in with the 炭斗, and because you need no 灰器, you close the door with it 🤯. In my room, the steps are a bit odd. Remember to take small steps once on the 手前座!
Put the 炭斗 down, remembering to leave enough room for the 鐶.
Shift in front of the 釜, and unpack the 炭斗 as you would normally in 逆勝手 with the L (still 羽・鐶・箸・香合). Place the 羽 and 火箸 close to the 畳 border, because you need the space above them for the 香合.
For the 香合, though, you take it with the R. In my case, that means that I have to shift ever so slightly to make it look comfortable. Place it above the 羽.
Open:
Close 釜 lid, attach 鐶, take out 釜敷 (place to your L), shift forward, take 釜, shift to 45°, place 釜 in the middle of the 畳 and the 鐶 on the ¼ line. Shift back to end up in a very comfortable distance.
With the 羽, unfortunately, you need to pick it up with L and then do the purification with R. It's 10 strokes for the first feather (and then 6 and 6). The feather then lives diagonally between the 炭斗 and the 釜 to your L.
Take 火箸 L, R (undergrip), adjust grip in front of your R knee, and move starter coal.
灰:
Because there's no 灰器, leave the 炭斗 where it is.
Just take the 灰匙 with R and scoop the ash. You start close to the 雪輪, from bottom to top and make a diamond shape as you would normally (just rotated by 90° CW). Even the re-holding for step 4 is quite easy.
The middle feather is 6 strokes. It only cleans the 炉壇, because the 灰 never goes over the 炉縁!
炭:
Take 火箸 with L, take the handle with R and turn their tip towards the 炭斗, then keep them in L to take the 同炭 with R.
Adjust the grip in front of your R knee, then take the 炭 from the R side of the 炭斗 and fill it in on the side closer to the 雪輪. The 枝炭 end up closer to the 炭斗 with their bottom ends.
When putting the 火箸 back (with L), make sure you make them peek out enough so you can easily take them with an underhand grip later when handling the 香合!
Final feather is again 6 strokes. It goes onto the 炭斗 afterwards as always.
香:
The lid squats relative to the middle of the 炭斗. From there, directly take the 火箸 with R with an underhand grip, rehold and put the 香 into the hot ashes. Place them back again with that underhand grip.
After the 拝見 request, you place it again where it was before (only turned).
Close:
Shift to 45°, get the 釜, put it in, get the 釜敷, adjust, put the 鐶 into the 炭斗.
Shift so that the 炉縁 line is in your middle to pick up the 炭斗.
座箒:
Because I don't have the dust hole, I come in with the 座箒 in R and the dust bin in L. Place the bin at the end of the line marking the 手前座, then step in with 5 steps.
Keep sitting on your heels. Hold your R knee with L, and shift towards the exit as you sweep.
10 strokes (6 is re-held), stand up, take the dust bin and 建水まわり.
Place 座箒 onto the bin and close the door.
Post 拝見:
Come in and sit in front of the 釜. Clean the 炉縁, clean the lid and open it.
Then shift to discuss the 香合. If they're nice guests, they put it on the 点前 side of the 釜.