I can formulate my own insights, but I think this website/blog (and click on links in it to get a more nuanced picture) is quite nice.
Legal Theory Blog: Legal Theory Lexicon: Rules, Standards, and Principles (typepad.com).
However, one should keep in mind that usually, the concept of RULE is described within an ideological framework that assumes that it is possible to formulate clear and unambiguous expressions of a type: if A is the case, then X should be done (so-called RULES) and therefore one can characterize standards and principles as more open. From my work (for example, CLEAR CASES, DO THE EXIST?) it will become clear that I deny this possibility of rules that lead to clear cases, a denial based on semiotic considerations. This of course makes the distinctions between rule and principle also less clear, mere a matter of ideology, or social-political context: a rule is not such a clear statement, but the legal society (or part of it) declares/constructs it as such.
International law, also called public international law or law of nations, the body of legal rules, norms, and standards that apply between sovereign states and other entities that are legally recognized as international actors. The term was coined by the English philosopher Jeremy Bentha
Indeed, the Principles are proposed as optimization mandates of certain values, which in turn seek to give coherence to the ordering. That is, of all the norms, including the rules.
An international legal principle is like a lens to view things through, while an international legal rule determines the outcome on a matter based on conditions and circumstances set forth in the rule irrespective of the view. A principle may animate what value and weight to give those conditions and circumstances, but a rule determines the decision after such value and weight are accorded and upon established facts. In practice, many courts apply principles as if they are rules, rules and principles can be equated and conflated, and principles often animate the enactment of rules, but strictly speaking the two are distinct yet converge in the decision-making process and decision.
principles are based on itselfes and are accepted as they are but rules are based on principles and are accepted becaue of the existing accepted principles
Of course, the rules must comply with the principles, because they are the basis of legal regulation. The rules ensure compliance with the principles. There is no other mechanism to ensure compliance
If we disregard the term (international) and want to know the difference between legal rules and legal principles, then we say: rules are singular as a rule, and they are what others are built upon. It is based on a set of rules as in the principle (no harm), according to which a set of rules working in various branches of law was established, and it seems that the relationship between principles and rules is a general and specific relationship, as the principle is more general and the rule is more specific.
International rules impose all of common states which accept the rules also enforce the states to apply the rules but international principles almost refer to customs which appear on during long term between different societies and are respected by them based on rationality and traditions.
The principle is the fundamental idea of what the rules must be based on. In another context, the principle is the blueprints, and the rule is what is built based on that.
Answer depends on approach to sources of law - positive or natural. In one case principles are based on Natural Laws (Physics, Biology etc.) and experience of mankind and rules just depict the ad hoc solution which is accepted in particular period of time. Otherwise rules are main source created by human genius and principles are just consensual, experience based guidelines for rules of same kind.
I may only add that Principles usually, but not always, originate in soft law, i.e. the 1972 Stockholm Declaration. International rules come from legally binding treaties as the 1997 Ottawa Mine Ban Treaty.
International legal rule and International legal principle; Legal rule and legal concept ordinarily to me are the same. It is just a matter of symantic. Legal principle is the basis of legal rule. Without legal principle, there can be legal rule. Legal concept is the means to an end of legal rule. The dual concepts are inseparable from one another. They are intertwined. That's, without the legal principle, there can't be legal rule.
Generally speaking, legal principles contain a wider range of topics than legal rules, also the former is better supported by legal regimes with more efficient sanctions than the latter.