Sewing method and sewing machine for releasing a tension thread from a passage formed by a stitch

A method for sewing, on a piece (1) to be sewn and according to a direction of sewing, a stitch (3) consisting of threads, known as auxiliary threads (4), by means (5, 6, 7) for picking up, of a sewing machine, this stitch (3) forming a passage (P), which extends in the direction of sewing (D), with a thread, which is known as the tension thread (8), which is guided and put into position in this passage (P) simultaneously with picking up of the auxiliary threads (4), to be able to slide longitudinally and/or laterally in this passage (P), wherein there is displaced transversely relative to the means (5, 6, 7) for picking up, at least one portion (37) of the tension thread (8), which extends from upstream and immediately to downstream from the means (5, 6, 7) for picking up, between a normal position for putting the tension thread (8) into position in the passage (P), and a position for release of the portion (37) of the tension thread (8), in which the latter is inclined relative to the direction of sewing (D) of the stitch, and passes opposite the means (5, 6, 7) for picking up, beyond the area of action of the means (5, 6, 7) for picking up, and beyond the passage (P), in order to permit cutting off independently of the auxiliary threads (4) of the stitch (3) and/or of the tension thread (8), by at least one cutting blade (16, 17) which is disposed downstream from the means (5, 6, 7) for picking up, and/or formation of loops (62) of the tension thread (8), which are released from the passage (P), whilst sewing is taking place.