This is all third hand, speculation and out right guesses
1. Devastation. I suspect that the early estimates for loss of life are off by a factor of ten
2. Very little communication in or out. Phone lines and cell service out for several days.
3. Japan is very well prepared for this; teams, supplies and systems in place.
4. That being said this will be a major challenge
5. The first thing that happens outside the area of destruction? You wait. Wait for info, wait to contact people affected, wait to be deployed. Where I used to live the first thing snowplow drivers did when there was news of a major storm approaching? Take a nap. might not be bad advice.
Teacher
The Japanese have invested huge amounts of resources into emergency services, hardening, and response coordination. Communications are seen by them, quite rightly, as even more vital than training and responders simply because if you can't figure out who needs what, and what resources remain, you can't even begin to cope.
The Japanese warning system is a decade more advanced than anything we have in the US. Their early detection systems gave a full minute of warning. This allowed bullet trains to start to come to a safe stop, allowed assembly lines and industrial plants to be shut down in an organized manner, and is being credited with saving many lives.
Japanese building codes are quite strict in terms of earthquake resistance. The building may not, especially in such a large quake, remain usable but the buildings are designed not to collapse. People get a chance to get out. I fully believe that if this happened in the US we would be seeing far worse devastation. Even California building codes are but a shadow of the Japanese version.
There is little debate that the Japanese are most disaster aware and prepared society on the planet. That said this is a very strong quake and nothing made by man is immune to such forces. And word is there may have been another farther north.
I fear that the wrong lesson may be learned. That when the butcher's bill is paid it will be surprisingly light for the forces involved and that other, less organized and prepared societies, will slack off in their efforts.