"Phra" in Thai means "amulet", or "venerable", depending on its context. (anyone well-versed in Thai, please correct me. Thanks!) "Pidta" is a generic name for those amulets with this design: 1) it is an amulet depicting a Buddhist saint, sitting in a half-lotus or full lotus meditative sitting position, covering his entire face with his hands. What the amulet design signifies and its reputed powers: 1) Being free from the worldly attachments of man's desires (from his 5 or 6 senses) 2) Divine Protection from the worldly temptations 3) Protection from one's enemies, such as Invisibility from Enemies (signified by the covering of the monk saint's eyes) 4) Invulnerability (or Impenetrability) to weapons (eg: knives) 5) Protection from Black magic 6) Protection from malevolent/evil spirits and other lower-level astral entities 7) Evasion of danger and from one's enemies According to my research, there are many variations on how this design of amulets came about. This is one version: There once was a formidable fighter named Bagawan (or Bakawan) who lived in a village. After his wanderings (presumedly to test his fighting abilities), he returned to his village. During his wanderings he had converted to Buddhism. After his return, for those who wanted to take revenge on him (for reasons I am unable to determine), he accepted it. He would just cover his face and let his enemies and former enemies beat him, accepting his bad karma.
For Malaysians in the amulet circle, the Tok Raja needs no introduction. He is well known and even well respected by the Sultan of Kelantan. Here is some information I got from a Singaporean Thai amulet forum (with major editing by me for stlye and expression): In the jungles of Malaysia and Thailand, there is a kind of tree which can release a kind of gas to protect itself. In Malaysia, it is known literally as the "Paint Tree"(translated from Mandarin). This kind of tree has a natural mechanism in protecting itself: it will release a kind of acidic gas that keeps human beings and wild animals away. It is a sophisticated form of natural chemical warfare and protective mechanism. If a human passes-by the tree, his body will feel itchy and swollen. The sap (liquid) of "paint tree" is red in color, and when it dries, it will turn into black. If a human being uses his hands to touch the sap of the tree, he will feel hurt by what feels like hot acid. In serious cases, his skin will be burnt. Tok Raja planned to use the sap of this particular tree to make amulets. He believed that since this kind of tree is good in self-protection, if he used the sap, together with his own powerful chant in the process of amulet-creation, these amulets would bring great protection to the wearer. Therefore, Tok Raja decided to use the sap of the "Paint Tree" to make pidta amulets because he knows pidtta can bring great protection and avoidance of danger by its wearer. The Pidta mould/design of amulets by itself is supposed to grant the wearer protective powers. It was believed that when Tok Raja used his own hands (without protective gloves) to get the sap (liquid) from the "paint tree", he was not hurt by the sap's acid, and the amulet(made by the sap of "Paint Tree") wearer will also not have any infection on his skin. As Pidta Amulet (from "Paint Tree" sap) was made by Tok Raja personally with his own hands (and not mass-produced by factories), the quantity of these amulets is relatively small, and its price consequently high.