boxwood cut off

I recently acquired a boxwood from a friend of mine. It was at the time part of his hedge that was planted in his grandfathers yard when he first built the house. All but three main limbs were cut off (i guess he remembered me a lil to late) anyways as I was looking at it I came to the conclusion that the best thing to do (if possible) was to cut back to the main trunk itself and allow new growth from there. The trunk is roughly 8 inches tall and about 4 to 5 inch diameter. So my question is, is it possible to cut so much off and if so when would be the best time to do so. Not sure of the exact kind, nor was he but I do believe that is a japanese. If pics are needed let me know

Survival is key at the moment. What is it planted in? Does it have any leaves left on or was it chopped back hard? When was it lifted? If this year, I wouldn't do anything until next spring, at the earliest. Pictures are always useful to assess what you've got and what to do, eventually.

It is planted in 10 gallon black pot in 30% regular potting soil at the time. There are still leaves on it but as you can tell chopped back pretty hard. By the looks of the lower trunk they started to snatch it with a chain but ended up lifting. I have had it since around Feb of this year, not sure exactly when it was lifted though and many knew leaves have came out, Red lines on pic show where all new growth has occured. If it is possible to cut all the way to tghe trunk then the other limbs will of course be used for cuttings, 4 plants from one lol.

Right, the pic and details make it a lot easier. Do nothing other than water and maybe a low nitrogen feed. Then next spring you could air layer the tops of five of those branches. They are quite easy from thin cuttings but I do mine in July. Hardwood cuttings are usually done around October but I don't think that thick cuttings of box will root. I may be wrong but I've never tried.

Once the tops are removed you can shorten down to just above the lowest leafy growth and then leave well alone and see what pops lower down.

The mix looks a bit water retentive. Just watch you don't keep it too wet.