Experiments are performed to confirm the chemical etching method for defining the crystallographic orientation of silicon single crystals. The best compositions of the polishing solution for the crystal surface and of the etchant for revealing dislocations are given. The etchant is not sensitive to crystallographic surfaces, and is capable of revealing both edge and screw dislocations, also "new" and "old" dislocations.The following experimental methods are used to verify the correspondence between dislocations and etch pits in the silicon crystals: 1) prolongation of etching time; 2) alternate polishing and etching; 3) etching of matched cleavage faces; 4) observation of dislocations in small-angle tilt boundaries and determination of their geometrical properties; 5) observation and determination of the geometrical arrangement of the etch pit patterns on different crystallographic faces of the specimens under deformation (bending and indentation); 6) checking of the relationship between the radius of curvature and the dislocation density of bent specimens.