Buckle, and method of decoupling female and male parts of buckle

A buckle comprising:

• a female part including a female portion in which a female channel and an aperture are formed, the female channel having channel ends on both sides in a width direction of the female part, and the aperture opening the female channel forwardly of the female part;
• a male part including a male portion and a main body interconnected to the male portion rearwardly of the male part, the male portion being inserted and retained in the female channel of the female portion, and the male portion including a leaf spring which is elastically bendable and deformable responsive to external operation using a cord, wherein
• elastic deformation of the leaf spring enables engagement between an engagement protrusion and a protrusion-accommodating portion, thereby preventing the male portion from moving inside and along the female channel,
• the engagement protrusion is releasable from the protrusion-accommodating portion as the leaf spring bends and deforms responsive to the external operation using the cord, and
• the female portion has at least one access-window through which external force is applicable directly or indirectly to the leaf spring for releasing the engagement protrusion from the protrusion-accommodating portion in a state where the engagement protrusion and the protrusion-accommodating portion are engaged so as to prevent the male portion from moving inside and along the female channel.