As the name of the yoga suggests, Siddha Yoga as per Hindu astrology gives a planetary combination that ensures success in all undertakings. The consensus is that when the lord of the sixth house is debilitated and that of the tenth house is deeply exalted, siddha yoga will arise. As a consequence, the person will be happy, victorious over his enemies, successful in all ventures and long-lived.
If the Siddha Yoga is really powerful, the person will hardly meet with failures or disappointments. The sixth is a dushta sthana (bad house0 and when its lord is debilitated, then all the indicators of the sixth house namely debts, disease, and enemies, will be fewer so that the obstructive force in the way of the person’s prosperity will have been removed.
The lord of the tenth house of effort, occupation, and deeds will have to be in deep exaltation, else siddha yoga cannot have its full value. In fact, this yoga ensure success by not only removing all the obstacles but also ascertaining that there are no half-hearted efforts. This is called siddha yoga, because it has perfect plans for success. It is also called Jaya yoga