Kṣetrajña — The Knower of the Field
Kṣetrajña ('knower of the field') is the Bhagavad Gītā's powerful designation for the jīvātmā, introduced in Chapter 13. 'This body (kṣetra) I call the field; and the one who knows it I call the knower of the field (kṣetrajña)' (13.2). The entire chapter unfolds the distinction between body (kṣetra) and soul (kṣetrajña) as the key to understanding the self.
The kṣetra (field) includes not just the gross body but also the subtle body — mind (manas), intellect (buddhi), ego (ahaṅkāra), the five sense organs, the five motor organs, the five vital breaths (prāṇa), and the five sense objects. All of this is achit — insentient matter. The kṣetrajña (soul) stands apart from all of this as the pure conscious witness (sākṣī) who knows the entire field without being reduced to it.
The verse 13.2 adds a crucial point: 'And know Me also to be the kṣetrajña in all kṣetras.' This is Bhagavān declaring His status as the Inner Controller (antaryāmi) within every soul. There are thus two levels of kṣetrajña: the individual jīva who knows its particular body-field, and Bhagavān who knows all kṣetras (all bodies and souls) from within. This verse is the scriptural basis for the Viśiṣṭādvaita understanding of the antaryāmi relationship.
For the Śrī Vaiṣṇava practitioner, the kṣetra-kṣetrajña distinction is the first step of ātma-jñānam. Recognizing 'I am not the body, I am the kṣetrajña' frees the soul from false identification with caste, family, and physical pleasure, and opens the door to understanding one's true nature as śeṣa of Bhagavān.
Rāmānujāchārya's commentary (Gītābhāṣya) on this chapter is a masterpiece of Viśiṣṭādvaita exegesis, showing that the kṣetrajña is not Brahman (as Advaita holds) but rather the individual soul who exists in a permanent distinction-in-unity with Brahman — both real, both eternal, both forming the complex unity of Bhagavān's body-soul relationship.