Well, in addition to the three main requirements, Casio decided to endow all G-Shock with another seven more that they must all meet today. The known ones like "the 7 elements" of G-Shock are:
-1 / Resistance to the electrical discharges.
-2 / Resistance to forces G.
-3 / Resistance to low temperatures.
-4 / Resistance to vibrations.
From here a subdivision is made taking the three fundamental principles of the G-Shock concept:
-5 / Resistance to impacts.
-6 / Resistance to water.
-7 / Hardness and durability.