This is also sometimes called a Chinese frog fastener or closure. This is a variation on the button style closure but, instead of a button, cord or a corded fabric tube is used to make an ornate knotted ball and a closing loop. The knotted ball passes through the loop to hold the garment closed. They tend to be very decorative and ornate and are frequently used on outerwear and military style jackets as well as traditional Chinese clothing. Because they are heavy, they need to be used on sturdy or stiff fabric.
The example shown here is one of the more ornate styles that I have seen. Flat silk ribbon was used instead of the more usual round cord. It has been formed into the shape of a lotus flower on each side of the frog closure.
Hook and Eye
This is a two part fastener that is made of metal - one part is a flat loop and the other is a hook. One part is sewn opposite the other, through the smaller loops at the opposite ends. The closing action occurs when the hook is slipped through the loop. The most common use of this type of fastener is on foundation/support garments because they are easy and quick to fasten and unfasten. They are also frequently used at the top of a short neck opening or above a zipper to hold the uppermost edges together. They work best when there is constant pressure holding them apart, because when the tension decreases the hook can easily slip out of the loop.
There is a heavier duty variation than those shown here that has a flat bar and a larger, more solid loop piece that is frequently used on men's slacks.