Sorry this is a long one. Trolling aside, declarations of martial prowess aside, testimony about how great we all are at what we do or how great our teachers are aside...
I think it'd be useful to at least attempt to try the 'internal how to' debate. For the purposes of at least trying at having a decent discussion let's assume and not question that Mike Sigman can do this internal stuff, Dan Harden can do this internal stuff, others can do this stuff. Let's also assume that Aunkai, Ki-aikido and CMA internal training methods Dan's stuff etc.. are all basically aiming for the same end, an end we might call Aiki. I know, broad assumptions but we've got to start somewhere. Also let's try to divorce the martial efficacy discussion from this. I don't think it's useful to argue the validity of a method by saying that it wouldn't provide useful fighting skills in this discussion. Yet. Aikido waza and how they compare to MMA or CMA or whatever isn't going to help the 'internal how to' discussion.
I'll start by describing a few beginner level ki aikido tests (i.e. stuff that will take you to the early dan grades in ki soc derived styles).
For all the below tests the levels as they are applied are as follows:
1) Basic coordination by applying light and increasing pressure (you should be able to pass these tests easily after 6 months to 1 year of training maximum)
2) Uses a fake or hesitation before the test is applied in order to determine if the receiver has a calm mind, if they don't they will move by anticipating the test and try to push into it and resist the testers application of ki.
3) Receiver must not allow testers ki to enter their body. Tester often approaches test with 'intent' before applying a strong test in which the tester extends ki powerfully.
I'll describe a number of different tests (there are many). The tests should not be confused with being used purely for assessment and rank advancement, the word 'test' is a bit of a misnomer in this respect. They are learning tools. Intended to be used to allow a student to gain feedback on their attempts at using internal power, in order that their instructor can determine their ability and help them to improve it.
. (often totally misunderstood by even the most well-read) receiver extends their arm elbow should be unlocked and arm slightly curved. Testers hand is rested on the bicep area. Testers other hand at the beginning is applied to the wrist, later tests can be applied to hand and fingertips.
. Receiver stands with feet shoulder width apart. Weight on the balls of the feet not the heels. Upright posture. Knees unlocked, hands resting by their sides. Test is applied between the shoulder blades or (in the beginning) on the front of the body at the shoulder. Later tests involve tester walking in with 'intent' from a few steps away.
Walking forwards whilst being held from behind
. Tester stands behind receiver and places hands on the front of receivers shoulders at the tops of the pecs below the collar bone. Receiver then tries to walk forwards. If receiver isn't moving from their centre their legs will try to move first and they will let their shoulders remain behind by yielding to the pressure being applied by the tester. After walking 5-6 steps tester suddenly lets go. If receiver lurches forwards they fail, this is because they have been physically pushing against tester by using physical strength instead of moving from their centre.
. Varied tests, count 1 for receiver to execute fwd part of movement, 2 for the return. At 1 tester may hold receivers wrists and either push or pull them (they do not indicate which one they will do). Hands may be placed under receivers arms and tester may try to lift them. Tester may also push between receivers shoulder blades. On no 2 count, receivers hands should be by their sides. Tester my pull receivers hands downwards or push upwards. Tester may place hand on receivers shoulders and pull straight back.
. For beginners, this is done with one foot in front of the other, later, feet are side by side. Receiver leans back (bad idea to let their head tilt upwards, receiver should keep eyes front). Tester places hand on shoulder of receiver and pulls straight downwards, later tests may be done by tester placing hand on top of receivers head (not for beginners though).
As previously said these are called 'tests' but they should properly be considered learning tools more than a method of rank assessment. They are only a sample of the many tests available.Eventually, you should be pretty much solid as a rock. Note that they do not necessarily teach fajing or explosive power release as Akuzawa (and others) demonstrates in videos I have seen. But IMHO they are the basic skill needed to achieve fajing and if you can do the above mentioned things then you have the internal skills and the stability with which to do fajing type stuff. I personally view fajing as an application of these core skills, some of the explosive power release is quite intuitive if you have the above developed skills. But like all else, if you don't train for it you don't get it. Or to put it more simply, in the Aunkai vids I've seen on youtube I know I can't kick as powerfully as that (at least as best as I can tell from a video). But. I do know that I can kick and punch more powerfully than many people I know who are karateka, Muay Thai fighters etc would expect me to be able to. Hence my reasoning that the ki tests and the skills that they develop are related and complimentary to explosive power release methods (I have sooo gotta find a way to train with Akuzawa sometime in the future to find out what % of what I just said is actually BullSú"^.....
). Please note, none of the above tests are well descirbed, the descriptions are brief and it is easy to assume that you can do them just by reading what has been written. The only way to really know for sure is to find a qualified instructor to help you learn these things. The tests can be deceptively simple, they are subtle and my vague descriptions are but the tip of the iceberg. If anyone does want to try them, please do so and then describe in as much detail as possible what you found happened (every detail helps), I may be able to give further clarification from this post. I'm sure others might chip in too.
Right. Now, in as constructive and positive a way as possible. Rip it all apart so I can learn some good things.