Evolution of the Concept and Symbol of Śunya

From prehistoric times, the Indus valley civilization (abbr. IDC) and the contemporary civilizations (China, Sumer/Babylon) in the Eurasian continent continued their counting with short line segments (horizontal or vertical or both) termed rod numerals without any ideographic representation for a void. In the fourth century BC, when China started using counting boards and adopted a system of counting with the base ten and a void by a gap, and between two consecutive rods, the Sumerians/Babylonians practicing the same had an occasional notation of a void by a pair of slanting wedges. In India (IDC), a philosophical idea of a void had by that time emerged in the form of Vaiśeṣika sūtras of abhāva and ākāśa due to Kaṇāda, and in conformity with the philosophy, the elites selected a group of words chosen for a void and numerals (used and continued later). With the advancement of civilization, a series of Upaniṣads (like Taittirīya, Kena, Chāndogya) evolved, focusing on the round Universe as the one representing the Space Supreme, the whole termed Brahman. By the early sixth century BCE, when Jainism dominated in the religious field in India, the round symbol, which is a monotheistic idea of Vedic origin (considered as the replica of the unknown Brahman, the Space supreme), became a sign for an unknown quantity in mathematics and a dot for zero which Piṅgalācārya (4th/2nd century BC) was the first to recognize as an integer.