Mars Yantra (Mangal Yantra)

I am going to post yantras of all 9 planets
in a series of post taking one yantra per post. These yantras can be
used to reduce the malefic effects of the corresponding planets. This post is the third in the series after Sun Yantra and Moon yantra. (Android users who are watching this post through my app (Astro Junction App) on their smartphones, should click on the title of the post above