If Yantras have a more defined role in Tantric ways of worship, then why householders or those not following Tantric methodologies insist on keeping Yantras at their places of worship? What is the overall role of Yantras in the Vedic/Tantrik worships? Are yantras used in Vedic Are the Yantras mostly associated with female form of the Lord?
What are yantras?
The word yantra is derived from the root 'yam', meaning to control. As worship of this helps to control all the internal and external enemies, it derives the name 'yantra'.
In what kind of Hindu ritual are these used?
Yantra is a part of the worship of the Tantrik deities.
According to Sritattva-chintAmani (17/2)
yamayati akhilam pApam trAyate mahato bhayAt/ sadhkam pujanad dhyAnAd tasmAd yantrah prakirtitah // meaning that a yantra when worshipped and meditated upon destroys all sins and removes all great fears and so liberates the aspirant.
According to Tantra, Yantra is a form of DevatA. It is also known as the dynamic graph of the Energies of DevatA. It is a body of the Mantramayi DevatA.
yantram mantramayam proktA mantrAtmA devatA eva hi/ deha-Atmano yathA bhedo yantra-devatayos tathA.
Shakti-Sangama-Tantra (13/203) says
yantram tu griham iti uktam grihasthA devaytA matAh, meaning that the yantra is the house where the devatA resides.
What is the overall role of Yantras in the Vedic/Tantrik worships? Are yantras used in Vedic Are the Yantras mostly associated with female form of the Lord?
As stated earlier, Yantra is a form of the Devata as is the image. There is an instruction in the Satapatha-Brahmana (7/4/1/10) that instructs to worship the Surya-Mandala engraved on a gold pot as a symbol of Surya-DevatA. The 'Sarvato-Bhadra-MaNdala'-s are used in the Puranic worships.But the Yantras are used only in the Tantrik worships. The Gandharva-Tantra (5/1) says
vinA yantrena chet pujA devatA na prasidati, meaning the Deity is not pleased unless His/Her yantra is worshipped.
Yes, Yantras can be used in worship of ALL (male and female) Deities. The ShaktAnanda-Tarangini says (Uttar, 13)
sarveshAm api devAnAm yantre pujAprashasyate, meaning worship of the Yantras is advised in case of ALL the Deities.
Alongwith the Yantras of the female deities, the yantras specific for the male deities like Sri Krishna, Sri Hanuman etc are available in the Vrihat-TantrasAra.Also, there is mention of one common Yantra which can be used for the Deities for Whom no Yantras are prescribed. However, there is a catch here:
pratimAyAm cha pujAyAm na likhed yantram uttamam (Matrikabheda-Tantra,12/6): meaning Idol and Yantra should not be worshipped simultaneously.
If by chance both are present in the place of worship, they have to be worshipped SEPARATELY, ie double puja, vali ang yajna are required (Matrikabheda-Tantra, 12/9-11)
If Yantras have a more defined role in Tantric ways of worship, then why householders or those not following Tantric methodologies insist on keeping Yantras at their places of worship?
It is clear from thevabove quotations that the common public should not keep any Yantra at the places of worship as they generally keep images/idols of the Deities and formal worship is not performed on a regular basis. Yantras should be worshipped only by those who practice Tantrik sadhana and worship on regular basis. So those who insist on keeping them must be unaware of the scriptural injunctions.
Reference: Sastramulak Bharatiya Shaktisadhana,Upendrakumar Das, RMIC, vol.2, chapter 17.