Acala Vidyaraja (不动明王)

Who is Acala? Acala or the Immovable One is the Chief of all Guardian Deities in Buddhism. He is actually a manifestation of Maha Vairocana, the Universal Buddha, in the form of a wrathful servant who protects all Buddhas. In his hands he holds a flaming sword which represents the wisdom that is able to cut through all defilements, as well as a rope which represents the skillful means to snare all wayward sentient beings to the Dharma. His halo of flames represent the power of his Samadhi, which although unmoving, can appear anywhere in the universe. Thus he is called the Immovable. It also refers to the Buddha-nature in all of us. I've a fond liking of Acala since young, when I first came across this deity in the Japanese manga, "The Peacock King". I thought he was a pretty cool guardian deity, sort of like an enlightened warrior servant.

The Mantras of Acala 不动明王 are 4 in number.
真言有殘食咒、火界咒、慈救咒、一字心真言等之別，其中，

Mantra of Ferocious Eating 殘食咒為：

曩莫三曼多縛日羅赧
(namah samanta vajranam，歸命普遍諸金剛）
怛羅吒（trat，殘害破障）
阿謨伽戰拏（amogha canda，不空暴惡）
摩賀路灑儜（maha rosana ，大忿怒）
娑頗吒野（sphataya，破壞）
吽（hum，恐怖）怛羅麼野（tramaya，堅固）
吽（hum）怛羅吒 （trat） 唅（ham mam，種子），
此出自底哩三昧耶不動尊聖者念誦秘密法卷中。

Mantra of the Fire Realm 火界咒為：

曩莫薩縛怛他孽帝毗藥
(namah sarva tathagatebhyah，歸命一切如來）
薩縛目契毗藥（sarva mukhebhyah，一切諸面門）
薩縛他（sarvatha，一切處） 咀羅吒（trat，叱呵破障）
贊拏（canda，暴惡）
摩訶路灑拏（maha rosana，大忿怒）
欠（kham） 佉呬佉呬（khahi khahi）
薩縛尾覲南（sarva vighanam，一切障礙）
吽（hum，摧破）怛羅吒（trat）
憾（ham mam，種子），
乃出自金剛手光明灌頂經最勝立印聖無動尊大威怒王念誦儀軌法品。

Mantra of Compassionate Rescue 慈救咒為：

曩莫三曼多縛日羅赧
(namah samanta vajranam，歸命普遍諸金剛）
戰拏摩訶路灑拏（canda maha rosana，暴惡大忿怒）
薩頗吒也（sphataya，破壞）吽（hum，恐怖）
怛羅迦 （ traka，堅固）
悍漫（ham mam，種子）

The Heart Mantra 一字心真言為:

‘南麼三曼多伐折羅赧悍’，
(namah samanta vajranam ham 歸命普遍諸金剛種子）
此二者均出自大日經卷二普通真言藏品。

These mantras represent the various qualities of Acala. The Mantra of Ferocious Eating invokes his power to eat away all our karmic obstacles. The Mantra of the Fire Realm is able to burn away all our defilements. The Mantra of Compassionate Rescue represents his ability to protect all sentient beings, and the Heart Mantra brings out the immovable aspect in our Buddha-nature. Acala's sadhana (method) belongs to the carya tantra of the Vajrayana tradition and it is a powerful one. If a person of the right aptitude is initiated into this sadhana, constant practice will quickly lead one to enlightenment.