Given technique is called as:

Crown-Down Technique Numerous modifications of the original step-down technique have been introduced, including the description of the crown-down technique. The more typical step-down technique includes the use of a stainless steel K-file exploring the apical constriction and establishing working length.  In contrast, a crown-down technique relies more on coronal flaring and then determination of the working length later in the procedure. The more typical crown-down, or double-flare technique consisted of an exploratory action with a small file, a crown-down portion with K-files of descending sizes, and an apical enlargement to size  #40  or similar.  The original technique included stepping back in 1-mm increments with ascending file sizes and frequent recapitulations with a small K-file and copious irrigation. It is further emphasized that significant wall contact should be avoided in the crown-down phase to reduce hydrostatic pressure and the possibility of blockage. Several studies demonstrated more centered preparations in teeth with curved root canals shaped with a modified double-flare technique and Flex-R files compared to shapes prepared with K-files and step-back technique.  A double-flare technique was also suggested for ProFile rotary instruments.