At some big temples or museums, we often see Buddhistic statues named 如来 (Nyorai) or 菩薩 (Bosatsu). The difference between them is that Nyorai is the name for whom have achieved enlightenment and have become Buddha, and Bosatsu is the name for whom are training to achieve enlightenment.
Miroku-Bosatsu is one of Bosatsu who has the meaning of `Mercy' in Sanskrit.
It is said that Miroku-Bosatsu is promised to become Buddha and save people like Shaka after 5,670,000,000 years of Shaka's death (about 383 BC), so it is also named `Buddha of future'.
The posture raising the right hand up gently and showing the palm is called 施無畏印 (Semuiin), and has a meaning to tell listeners of preaching not to fear and to feel easy.
Sketched at Sekido Museum of Art