Core Teachings in the Tripura Rahasya

The core teaching in the Tripura Rahasya to "kill the thoughts" is not about a forceful suppression, but about shifting your focus to the Source of the thoughts and realizing the non-reality of the mind itself. This is primarily done through Self-Enquiry (Vichara), a method highly valued in this text (and by Ramana Maharshi).
The text emphasizes that restraining the thoughts is the best way to achieve the highest state. This is accomplished not through battle, but through realization.
 
The key instructions to the mind are:

1. Engage in Earnest Investigation (Vichara):
2. This is the root-cause of everything and the first step to supreme bliss. It means a deep and constant inquiry into the nature of the Self, the world, and reality.
3. Action for the Mind: Direct your entire intellect toward determining the Truth and discerning all that is transient and illusory.
4. Seek the Self (The "Who Am I?" Inquiry):
5. The world and its sufferings are a creation of the deluded mind and vanish in the absence of imagination (Sankalpa).
6. Action for the Mind: Turn inward to search where the consciousness of "I" (the "I-thought") arises. By constant attention to the inner awareness of "I," you discover the unreality of the thought-bound ego.
7. Stop the Mind's Fluctuations:
8. The constant mental concepts and modifications (Sankalpa-Vikalpas) are what cause Samsara (the cycle of suffering). Samsara rises when the mind is active and ceases when it is still. Take the life easy and as it comes. All are equal as same almighty resides in each one.
9. Action for the Mind: Aim to still the mind by focusing on its source, or by controlling the breath (Prana) and the latent desires (Vasanas). The mind and breath are seen as inseparable, like two sides of the same coin.
10. Cultivate Dispassion and Association with the Wise:
11. Dispassion (Vairagya), or detachment from sensual pleasures, is a prerequisite because a mind rapt in the quest for truth must first be clean of worldly cravings.
12. Action for the Mind: Cultivate faith and associate with the Guru or wise (Sages) to gain pure-mindedness and the zeal for enquiry.

Ultimately, the thought is not "killed" by another thought, but dissolves when the mind realizes that the world, like a mirage, is not separate from the Supreme Abstract Intelligence (Consciousness), which is the Self. Once this knowledge is realized, the mind rests permanently in its true nature, which is bliss.