OM NAMAH SHIVAYA

OM NAMAH SHIVAYA is also called Panch-Akhshara mantra (meaning 5 syllabled Mantra):

na-mah shi-va-ya each syllable symbolises the 5 elements of nature that we are made of - water,earth, fire , air and ether respectively.

(water is blood, earth is flesh,air is the wat we breath, fire is the heat - energy realeased by break down of food, ether is a space above the air where it is said that heavenly bodies stay) - it is the mind.
so te repitition of the mantra cleanses our body. all the five elements are cleansed by this mantra.

If we go by the literal emaning of the mantra it means "I bow to you lord Shiva" or "I surrender to you Lord Shiva".

Now as we know that we have three lords - brahma the creator, vishnu the preserver and shiva the destroyer. Shiva is the 'Self'. like when everything is destroted .... only shiva remains. Similiraly when we leave this physical form .... only the Self remains.

so surrendering ourselves to the self means we are knowing more of our 'SELF'

the good thing about this mantra is that you do not have to have a certain place and a certain time to chant this mantra. this mantra can be chanted anywhere, anytime ...in the train,bus .while travelling,working etc..etc..

once we start chanting the mantra regularly....it integrates in our system....it kind of dissolves in us... them even without knowing we would be chanting this mantra.... but that obviously takes time and regular repitetion.