A key for locking a cylinder lock, comprising a. at least one first surface and at least one second surface , b. with sensing positions provided along the longitudinal extent of the key , c. wherein the first surface is provided with at least one code and the second surface is provided with at least one further code , d. wherein the codes comprise control points at the sensing positions provided transversely to the longitudinal extent of the key and arranged at certain control heights , which are connected to one another via control grooves , e. wherein at least three control grooves are provided, of which at least one is constructed as a deep control groove with deep control points , and the remaining control grooves are constructed as shallow control grooves with shallow control points , the deep control grooves having a larger groove depth than the shallow control grooves , and the shallow control grooves running essentially parallel to one another, f. wherein at least one control point is provided with a different dimension on both surfaces at at least one sensing position , i.e. with a larger diameter than the control points at the other sensing positions , characterized g. in that the control point with a different dimension is part of the deep control grooves which, starting from the key tip up to the control point , is designed as a deep control groove with a larger diameter , the diameter of which corresponds substantially to the diameter of the control point with a different dimension, h. wherein the deep control grooves on the key tip are arranged between the shallow control grooves and merge with them so that no separating bar of material remains on the key tip between the deep control grooves and the shallow control grooves . a. at least one first surface and at least one second surface , b. with sensing positions provided along the longitudinal extent of the key , c. wherein the first surface is provided with at least one code and the second surface is provided with at least one further code , d. wherein the codes comprise control points at the sensing positions provided transversely to the longitudinal extent of the key and arranged at certain control heights , which are connected to one another via control grooves , e. wherein at least three control grooves are provided, of which at least one is constructed as a deep control groove with deep control points , and the remaining control grooves are constructed as shallow control grooves with shallow control points , the deep control grooves having a larger groove depth than the shallow control grooves , and the shallow control grooves running essentially parallel to one another, f. wherein at least one control point is provided with a different dimension on both surfaces at at least one sensing position , i.e. with a larger diameter than the control points at the other sensing positions , characterized g. in that the control point with a different dimension is part of the deep control grooves which, starting from the key tip up to the control point , is designed as a deep control groove with a larger diameter , the diameter of which corresponds substantially to the diameter of the control point with a different dimension, h. wherein the deep control grooves on the key tip are arranged between the shallow control grooves and merge with them so that no separating bar of material remains on the key tip between the deep control grooves and the shallow control grooves . <EOS>