Rick posed a question in a comment yesterday - basically along the lines of, "Why do aiki/judo look different if they are the same thing?" There are several reasons that they really are the same thing but they end up looking different in practice. I want to consider three...
- They tend to approach power and strength from different sides. They both approach a common ideal - maximally efficient/appropriate use of power. But the aiki guys tend to approach that ideal from the use-no-strength side and the judo guys tend to approach that from the use-all-your-strength side. As aikidoka get better they learn to apply power properly and as judoka get better they learn to achieve their goal with less power.
- The two arts play mostly with different skillsets within the whole of jujitsu (See this Tomiki article). Aikidoka do more kansetsuwaza and striking, judo does a broader range of throws and grappling. Because of the variety of the whole skillset in jujitsu, it's hard to devise a randori ruleset where you can safely play all those skills. So the aiki guys (basically) took a different half of jujitsu to specialize in.
- The judo ruleset constrains judoka's behavior toward judo randori/shiai (e.g. ippon throws and either decisive groundwork or none at all) and the aikido emphasis on self-defense (particularly in the context of weapons and multiple attackers) constrains their behavior.
All of this is not to say that aikido and judo are different things. They are different lenses on the same thing. There is a lot of overlap despite their different specializations. Where you really see the similarities are in some of the higher judo kata (like Goshinjitsu and Junokata) as well as in some of the higher Tomiki kata (e.g. Sankata). In these exercises, judo becomes aikido and aikido becomes judo.
As examples of the above points, consider the exceptions...
- judo guys that refuse to work from hi-power and strength paradigm look more aiki-like
- aiki guys that use more physical power look more like they are doing judo's goshinjitsu kata
- judo guys who agree amongst themselves to play with strikes in randori either get busted up or they begin developing aiki-like rulesets and looking more aiki-like.
- Tomiki aikido guys doing toshu (empty-handed randori) have to have specific rules (like no grabbing the gi) to keep them doing something that looks like aikido instead of judo
...in other words, when you take either art and flex its rules or assumptions a little, you end up with the other art.
Patrick Parker, is a Christian, husband, father, judo and aikido teacher, Program Director for a Cardiac Rehab, and a Ph.D. Contact: firstname.lastname@example.org or phone 601.248.7282