Five physics mechanisms of interaction leading to the binding of the H-3(+) molecular ion are identified. They are realized in a form of variational trial functions, and their respective total energies are calculated. Each of them provides subsequently the most accurate approximation for the Born-Oppenheimer (BO) ground state energy among (two-three-seven)-parametric trial functions being, correspondingly, H-2-molecule plus proton (two variational parameters), H-2(+)-ion plus H-atom (three variational parameters), and generalized Guillemin-Zener (seven variational parameters). These trial functions are chosen following a criterion of physical adequacy. They include the electronic correlation in the exponential form, exp(gamma r(12)), where gamma is a variational parameter. Superpositions of two different mechanisms of binding are investigated, and a particular one, which is a generalized Guillern in Zener plus H-2-molecule plus proton (ten variational parameters), provides the total energy at the equilibrium of E = -1.3432 au. The superposition of three mechanisms, generalized Guillernin-Zener plus (H-2-molecule plus proton) plus (H-2(+)-ion plus H) (14 parameters) leads to the total energy, which deviates from the best known BO energy to similar to 0.0004 au, it reproduces two-three significant digits in exact, non-BO total energy. In general, our variational energy agrees in two-three-four significant digits with the most accurate results available at present as well as major expectation values.