The invention relates to a one piece blank of a corrugated cardboard sheet material designed for forming a belt intended to form a box having a length L, a width W and a height H, wherein this blank includes a main rectangular body (10) extending along a longitudinal direction and two protruding rectangular parts (11, 12) extending in a transverse direction and symmetrically with regard to the main body, so as to define two perpendicular branches, a first branch being defined by the main body and a second branch defined by the protruding parts, the main body (10) having a width (D1) larger than the length L and a length (D2) larger than at least twice the width W plus the height H (2W+2H) and each of the protruding parts having a length (d1) larger than the height H or the width W and a width (d2) larger than the width W or the height H.