Interestingly I just had a conversation with one of my juniors about this very thing.
I dont pretend to be 100% right. I have read what every expert in the feild ( masters standing in a open area I guess

) have to say about it, and I have taken this from it........
Each and every strike, kick, block and punch should be done with the spirit or mentality that this is the first, last and only technque that will be done. Then viewing a movie, frame by frame, the next technique is a new "frame", a new moment and completely separate from the last move.
Now the reason this came up is because my junior is very much into the sport of Karate and martial arts. Like me he is into Judo and he also does Jujitsu, were I did Sambo. We were talking about the fact that combinations dont fit into the concept of "one punch, one kill" and I had to agree. This is why Sport, MA training and self defense are all so vastly different. When you do sports you work to set up techniques, perform them, get a point and then move to the next point you want to score. In the Dojo you are repetitivly working on Waza with partners and obviously after a "sweep, punch" combo your partner gets up and you do it again. In the tournament you do it 70% full power and speed with 0% impact. In the Dojo you may go 50-80% full speed and reserve the impact to maybe 10% (depending on the dojo), but on the street you have to give 100% on both areas and prey you dont have to do that on the"Next" Waza as the fight should be done.....or theoretically it should be.
I have to say that I did a tone of tournaments when I was younger, and I did work out in the dojo twice a day for about three to four hours a day. and I still dont think that any of that lives up to the "real world" situations I had as a bouncer or the few unlucky times I actually had to defend myself.
In a tournament Ikken Hisatsu does not really come into play at all. In the dojo a little. Normally it is a concept that may be mentioned once or twice a week but really not focused on. In the few times I had to use Karate, that was the FIRST thing that jumped into my mind.
Again, to me....it means each technique should have the potential to end a altercation in its tracks. Will it....Probably not, but if you dont give 100% then you dont get that chance!
James. J
Even monkeys fall from trees