Colbs

Here's some random rambling on the topic:

You'll find most groundfighters don't use force against force, it just looks like it because of the extream close range they are engaged at, as they can't move far, they must make very small redirections of force, rather than the larger ones we're used to. If you're looking for direct application of aikido principle, go for a sankyo or nikkyo lock (wrist, ankle, whatever).

Against a good shot (takedown) the only thing that has proved effective to gain you position is the sprawl, against a crappy tackle, you may be able to get some tenkan and throw. But a tackle IS NOT a takedown, takedowns are not launched until they've closed into striking range and they're done quickly, and usually set up so as to take you by surprise.

As for the I want an "Aikido defense" - I'm sure I remember reading the founder saying that he practised aikido, therefore anything he did was aikido (or words to that effect). Striking (atemi) is not contrary to aikido, neither (IMO) is grappling, nor anything else.

If you want to know how to deliver strong atemi, you need to train with good strikers, if you want to know how to grapple well, you need to train with good grapplers. Aikido is a set of principles and philosophies, but often parts are glossed over, and assumed. I'm sure the founder assumed that all his main students knew how to punch (most came to him from other arts first), and at the time groundfighting wasn't the current fad, so it was probably not very emphasised. After all, the ground is the LAST place you want to be in any conflict (except in a ring, where there are no perhaps-not-quite-so innocent bystanders).

Crosstraining can only enhance your Aikido, it will teach you about weaknesses you have, and no-doubt re-emphasise just how useful it is as an art.