with reference first to the embodiment of an alpine ski boot illustrated in fig1 it appears that said boot ( 1 ) comprises a shell bottom ( 2 ) onto which is mounted a boot top ( 3 ) consisting of a front piece known as an oversleeve ( 4 ) and a rear piece known as the rear cover ( 5 ), at least one of which is articulated with respect to said shell bottom ( 2 ). in the case shown in the figure , rear cover ( 5 ) is assembled so as to be pivotable about an axis formed by a swivel rivet ( 6 ), so that said rear cover ( 5 ) may be swung rearward in order to permit the boot , now in open position ( not shown ), to be put on from the rear . in closed position , rear cover ( 5 ) is held against oversleeve ( 4 ) by closure and tightening means consisting of a an actuating lever ( 7 ) connected to a flexible loop ( 8 ) of a traction cable ( 9 ). said flexible loop ( 8 ) is fastened in a known manner to an anchoring stud ( not shown ) on the other side of oversleeve ( 4 ). actuating lever ( 7 ) cooperates with a rack ( 10 ) that is integral with the first side of said oversleeve ( 4 ). thus , loop ( 8 ), forming two cable strands , one upper ( 8 &# 39 ;) and the other lower ( 8 &# 34 ;), encircles the rear surface of said rear cover ( 5 ), which it holds against the oversleeve when in closed position . upper strand ( 8 &# 39 ;) is held in place by passing through a guide device ( 11 ) provided at the upper , middle part of the rear cover ( 5 ). said upper strand ( 8 &# 39 ;) is simultaneously able to slip freely while the tension of tightening means ( 7 , 8 , 10 ) is being adjusted , and to be held in the correct closed position along the top of rear cover ( 5 ). although it is not shown in fig1 a similar guide device ( 11 ) could easily be applied to the lower strand ( 8 &# 34 ;) of the loop . as shown particularly in fig2 and 3 , the guide means ( 11 ) consist of a kind of recessed key ( 12 ) having a generally u - shaped cross - section , and of an opening ( 13 ) the width of which corresponds essentially to that of said key , in the wall of rear cover ( 5 ). said opening ( 13 ) is situated approximately in the plane containing said rack ( 10 ), which is integral with oversleeve ( 4 ), thus ensuring proper alignment of loop strands ( 8 &# 39 ;, 8 &# 34 ;) and optimal tension of the tightening means . similarly , when lever ( 7 ) is uncoupled from rack ( 10 ) in order to open rear cover ( 5 ), upper cable strand ( 8 &# 39 ;) remains retained by recessed key ( 12 ), through which it is able to slip until said cover has reached the fully open position . during the entire motion of opening the boot , and while the boot occupies the open position , the closing means remain connected to said rear cover , it being impossible for the loop to assume any position other than that in which it is attached to cover ( 5 ). by virtue of the guidance and retention device ( 11 ) according to the invention , the end of loop ( 8 ) which passes through lever ( 7 ) remains in a position to allow easy and direct fastening by a skier , even a very young one , by allowing said skier to apply the lever against rack ( 10 ) without having to check whether loop strands ( 8 &# 39 ;, 8 &# 34 ;) are properly placed on the outer surface of said rear cover ( 5 ). in order to anchor recessed key ( 12 ) in the wall of cover ( 5 ), the two legs ( 14 , 15 ) of the u - shaped section each contain a groove ( 16 ) of a width corresponding to the thickness of the wall ( 5 &# 39 ;) of rear cover ( 5 ), as illustrated in fig6 . each leg terminates in a flange ( 17 , 18 ) that abuts the inner surface ( 5 &# 34 ;) of wall ( 5 &# 39 ;) of the cover so that the key will snap into opening ( 13 ) in said wall ( 5 &# 39 ;). advantageously , the height of opening ( 13 ) will be slightly less than the distance between the bottoms of grooves ( 16 ) so that legs ( 14 , 15 ) will be subjected to a slight stress when key ( 12 ) is mounted in the opening . the recess ( 19 ) in the u - shaped section of key ( 12 ) is oriented toward the interior of the boot top , making it impossible to lose the traction means ( in this case cable 9 ) which are loosely sandwiched between the outer surface ( 5 &# 39 ;&# 34 ;) of wall ( 5 &# 39 ;) and the bevelled body ( 20 ) of said key ( 12 ) ( fig5 and 6 ). the traction means are enabled to slip freely due to the fact that the opening ( 19 ) of the u is sightly wider than the diameter of cable ( 9 ). for other traction means , such as a strap , the same dimensioning principle would be used as is used here for the cable . as illustrated particularly in fig3 through 6 , retaining device ( 11 ) is mounted by inserting key ( 12 ) into opening ( 13 ) from the inside of boot top ( 5 ) as illustrated by arrow ( 21 ). cable strand ( 8 &# 39 ;) is inserted into recess ( 19 ) between the legs ( 14 , 15 ) of the u - shaped key while the latter , which has not yet been snapped into said opening ( 13 ), is situated opposite the inner surface ( 5 &# 34 ;) of wall ( 5 &# 39 ;). in order to permit it to be thus inserted into key ( 12 ), cable strand ( 8 &# 39 ;) is first formed into a temporary loop ( 22 ) and passed through opening ( 13 ), as illustrated in fig3 and 4 . the bevelled shape of the body ( 20 ) of key ( 12 ) facilitates insertion of key ( 12 ) within opening ( 13 ), aided further by the fact that the flexible legs ( 14 , 15 ) of key ( 12 ) draw together by compression , thus reducing the dimension of recess ( 19 ). the drawing together of the legs , illustrated by arrows ( 23 ), ( 24 ) in fig6 thus prevents the cable from escaping as the key is being set into the opening , by virtue of the fact that recess ( 19 ) is made smaller than the diameter of cable ( 9 ). finally , recessed key ( 12 ) advantageously possesses two insertion chamfers ( 25 , 25 &# 39 ;) disposed laterally on bevelled body ( 20 ). said insertion chamfers ( 25 , 25 &# 39 ;) have an angle of contact such that they define a free passageway between the perpendicular sides ( 13 &# 39 ;, 13 &# 34 ;) of opening ( 13 ) and the lateral edges ( 26 , 26 &# 39 ;) of bevelled body ( 20 ), the dimension &# 34 ; p &# 34 ; of said passageway being no less than the diameter of cable ( 9 ), or of the thickness of a strap or other connection means , as the case may be . while this simple and inexpensive device is particularly well suited to rear - entry ski boots equipped with systems using cables to close the top portion of the boot , it may also be adapted , as mentioned above , to systems using straps . in such cases , the shape and dimensions of the guiding device according to the invention shall be appropriate for the size and shape of said strap ( s ). it would also be conceivable to provide a ski boot , or a boot or shoe for use in other sports , with several such devices , which may also be applied to laces .