Shoe having upper and sole

A flexible member includes a reinforced area reinforced by first and second reinforcement portions, wherein: the area is defined by the posterior edge of a first reinforcement portion and the anterior edge of a second reinforcement portion; the first and second reinforcement portions are smoothly continuous with each other without gaps; the perimeter of the area is completely surrounded by the first and second reinforcement portions; the virtual first center line of the area extends obliquely forward and upward; and the angle formed between the first center line and the tread surface of the sole is about 40° to 55°.