With this question, I profess my ignorance of BJJ; but I have a question for you, Mr. Leavitt.
In your experience with BJJ/ground fighting, how would you say it fairs against multiple attackers at once; the 3-5 attacker randori one would expect to see in Aikido?
Hehe...boon answered it.
Seriouslly, this is a very tricky and loaded question. One that I demonstrated last week as to why it is important to have ground skills in a multiple opponent scenario.
It is difficult for me to answer as I am not a purely BJJ or Aikido guy.
Don Magee might pop in here and comment as well at some point.
To me multiple opponent scenarios are very tricky to answer as they present many variables.
However I had to answer in a few words without qualification...i'd say what Michael Fooks said "about as well as aikido".
How do you eat an elephant? One piece at a time.
Same with multiple opponents, but you may be able to multitask a little.
I think a strength that BJJ did give me is that when i used to get "tonque tied" in Randori, I can sustain myself a little better from training the clinch range whereas before, I'd get to fighting with the guy and not really know what to do inside that range except struggle.
I think there is a bit of dissonance in aikido that somehow randori as commonly practiced gives us "leg up" on other arts through a set of skills that translates to being able to handle multiple opponents, when in reality it does noy, the skills and principles we learn doing randori are technically correct, and may even apply tactically to a degree, but nothing translates in training to 100% reality (to include BJJ).
A big part of this, from my experience is that randori does teach and reinforce the importance of irimi, tenkan, and maintaining space and timing, and positional relation such as triangulation, entering and spliting opponents...but typcially stops the practice once you are "tied up" and the "fight begins".
BJJ typically trains from the point of failure (clinch) and works from there.
It is sort of like how Judo is commonly practiced. They get really good at the throws, but maybe not so good at newaza, because they emphasize a particular aspect of of the fight spectrum.
I tend to not practice multiple opponent too much as in eating the elephant you do this one piece at a time. I think it best to train from all ranges of combat with one person that is influencing closing distance (ma'ai) and then working within the clinch to ground work. then once you can deal these, occassionally your break up the spectrum of ranges and apply it to multiple persons.
An over generalization would be that aikido guys practice moving, irimi, tekan and avoidance and BJJ guys ignore this and move into the clinch.
in reality in a real fight as an over generalization, Aikido guys get caught and can't get out of the clinch and BJJ guys fixate on the clinch and get trapped by multiple opponents...hence they deal with it about equally as well!
it is all situationally dependent. We shouldn't assume that BJJ guys are so dumb that they don't know how to disengage and run. How fast do they have to run? Only a little faster than the aikido guy!
(couldn't resist that one!)