227. As a general rule

Extension and Abbreviation.

As a general rule, ch is not allowed by the grammarians to stand in that form after a vowel, but is to be doubled, becoming cch (which the manuscripts sometimes write chch).

a. The various authorities disagree with one another in detail as to this duplication. According to Pāṇini, ch is doubled within a word after either a long or a short vowel; and, as initial, necessarily after a short and after the particles ā́ and mā́, and optionally everywhere after a long. In RV., initial ch is doubled after a long vowel of ā́ only, and certain special cases after a short vowel are excepted. For the required usage in the other Vedic texts, see their several Prātiçākhyas. The Kāṭhaka writes for original ch (not ch from combination of t or n with ç: 203) after a vowel everywhere çch. The manuscripts in general write simple ch.

b. Opinions are still at variance as to how far this duplication has an etymological ground, and how far it is only an acknowledgment of the fact that ch makes a heavy syllable even after a short vowel (makes “position”: 79). As the duplication is accepted and followed by most European scholars, it will be also adopted in this work in words and sentences (not in roots and stems).