You get just as wet no matter where you jump in

One of the cool things about aikido is that there are no prerequisites. There is no ‘most advanced skill.’ You can work the skills in any order and call that a ‘system’. A beginner may jump in with the whole class profitably practicing whatever happens to be on the lesson plan for that day. Sure there are safety considerations - you don't make newbies take big falls - but they can still practice the same techniques and principles as everyone else. I've heard it said that there are no advanced techniques or concepts in aikido - just skilled students practicing the fundamentals in a very advanced way.

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Many Aikikai schools (if I understand rightly) start with ikkyo (oshitaoshi) as the first teaching, while most Tomiki schools start with shomenate as the first teaching and only get to oshitaoshi (Aikikai’s ikkyo) as the sixth teaching after several hours of practice. Either is an okay way of teaching the thing, and after a few hours of practice, it probably doesn’t matter because students of both methods end up understanding both concepts.

In some schools, there is this talk of omote (superficial techniques taught to anyone) and ura (deep, hidden teachings only taught to the initiated) but Musashi in the end of the Wind Book writes about there being no internal teachings and no gate:

There is no "interior" nor "surface" in strategy.

The artistic accomplishments usually claim inner meaning and secret tradition, and "interior" and "gate", but in combat there is no such thing as fighting on the surface, or cutting with the interior. When I teach my Way, I first teach by training in techniques which are easy for the pupil to understand, a doctrine which is easy
to understand. I gradually endeavour to explain the deep principle, points which it is hardly possible to comprehend, according to the pupil's progress. In any event, because the way to understanding is through experience, I do not speak of "interior" and "gate".

...Accordingly I dislike passing on my Way through written pledges and regulations. Perceiving the ability of my pupils, I teach the direct Way, remove the bad influence of other schools, and gradually introduce them to the true Way of the warrior. The method of teaching my strategy is with a trustworthy spirit. You must train diligently.

…In my Ichi school of the long sword there is neither gate nor interior. There is no inner meaning in sword attitudes. You must simply keep your spirit true to realize the virtue of strategy.

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