"Because we haven't fully matured ninjutsu has less utility for us as it's more costly as a proportion of total chakra than it would be for an adult. This comes from the concept of chakra advantage, which states that if you have spent less proportional chakra than your opponent in an otherwise equal exchange, you now hold the advantage. For this reason taijutsu and bukijutsu are the mainstay in early training."
This is, basically one of the axioms. In non-Naruto terms, If you spend a lesser fraction of your energy than your opponent, you're in a better position.
There are a few other, casually implied axioms too, like A weapon to any lethal point on your body will kill you. Armor does not apply, since if you hit armor, you aren't actually hitting a lethal point. Just the covering.
There are some, like You can't hit what you can't see/hear/smell/sense, or It doesn't matter if you can see it if you aren't fast enough to react, which are pretty much obvious.
Are these three enough to completely cover all potential situations? If not, what else must be added?