Step 1: Concept Identification: The query requires discerning the meaning of a specific Bhatkhande notation symbol for Hindustani classical music, namely the swara 'Ga' with an underline.
Step 2: Notation Breakdown: In the Bhatkhande system:
- An underline beneath a swara signifies a 'Komal' (flat) rendition. Applicable swaras are Re, Ga, Dha, and Ni.
- A vertical line above 'Ma' denotes 'Tivra' (sharp) Ma.
- An arc over a sequence of swaras indicates a 'Meend' (glissando).
- A smaller note positioned top-left of a main note signifies a 'Kan' (grace note). Consequently, \underline{Ga} denotes Komal Gandhar.
Step 3: Conclusion: The underline beneath 'Ga' conventionally represents the Komal Gandhar Swar within the Bhatkhande notation framework.