Several years ago when I revisited Camberley Judo Club, the club I
trained at during my competitive days in the early 90s, the coach there
asked me to give BJJ a try. They had sublet the mat to a BJJ class and
their judo players usually would join the class.
He then passed
me a white belt and said I should wear that in the BJJ class. It was the
right thing to do because I had at that point zero experience in BJJ. I
didn't know the rules, I didn't know the moves, I was an absolute
beginner.
The stark differences with judo became obvious to me
very quickly. Firstly, the moves they taught (for getting an armlock or a
strangle, for example) were really very elaborate and took a long time
to achieve relative to judo moves. I thought to myself, "That might
prove to be an effective move if you have the time but in judo, a matte
would have been called long before that happens".
When it came
time to randori, we started on the ground (there wasn't even a pretense
to start standing up). As a judo player, my instinct was to turtle up.
Later, I found out this was exactly what BJJ players would not do. They
never like to give their backs to the opponent. Instead, they pull guard
(and lie with their backs to the mat).
Back then, I didn't know
any better so I happily turtled up shielded myself from armlocks and
chokes. My training partner climbed on top of my back and clamped on but
wasn't able to really do anything. After a while, I thought he would
move to a different position and try something else but he seemed
content to clamp onto my back. Later, when I chatted with him, he when
he clamped onto my back like that, in BJJ it's a score.
After
the session was over, I went over to another judo guy and asked him what
he thought of the training. He said he does it because the coach asked
him to but he doesn't particularly like it because it's quite different
from judo, which was his focus. I felt the same way.
I know some
people who favor cross training point to the fact that the Japanese
national judo team does occasionally train with BJJ people. So, it must
be a good idea.
What they don't realize is that the Japanese
national team players train practically every day, at least twice a day.
They do so much judo that it would really be overkill for them to do
any more judo than they already do. So, they try other things like BJJ
to complement their training.
It's sort of like how rugby
players in the UK tried some judo to complement their rugby training.
These are professional rugby players who train rugby full-time. They do
so much rugby training, they can afford to do something a little bit
different just to offer some variety to their training.
For the
rest of us, we hardly have enough time to train in judo. How many among
us actually do judo six days a week? In my club only one or two players
do anything close to that. A small handful train three to four days a
week. Most train once or twice a week.
When the frequency of
training is like that, any spare time you have for training should be
spent doing judo, not some other "similar" sport. If you train in judo
so much (like the Japanese who train twice a day), yes, you can afford
to do other sports to add some variety to your training. But when you're
hardly getting enough training in judo itself, you should be doing more
judo (if you want to improve in judo).
Think about it. If
you're a badminton player who trains only a few times a week, if you
want to improve your badminton, you should be spending your time playing
more badminton, not playing tennis instead. Yes, both sports involve
racquets and both sports involve hitting an object back and forth on a
court but they are really not the same sport. Different rules, different
skill sets required.
Judo and BJJ might seem similar but even
the gis we wear are different (judogis are generally longer and looser).
The rules are very different. The scoring system is different. The
moves themselves are different. The style of play, the tactics, the
emphasis -- all different.
If I'm a Japanese player up to my
neck in judo training, maybe I would like to do some BJJ on the side.
But I'm not. I don't get as much judo training as I'd like so if I have
the time to do more training, I'd rather spend it doing judo.