Rule. In place of an ik vowel (i u ṛ ḷ, long or short) comes the matching yaṇ (y v r l) when a vowel follows, in close utterance. "Matching" is decided by nearness of place: i and y are both palatal, u and v both labial, ṛ and r both made at the roof of the mouth, ḷ and l both dental.
Example.
sudhī upāsyaḥ → the ī of sudhī is an ik; the u of upāsyaḥ is a vowel after it → the ī is replaced by the palatal yaṇ, y → sudhy upāsyaḥ.
Applies when / blocked by. Only within saṃhitā, the close utterance of chapter 1 (SK 28): the word saṃhitāyām is carried into this rule from an earlier heading. Scholars discuss exactly how the sūtra's wording secures that the vowel must follow immediately.
Watch out. The rule replaces the ī only; nothing happens to the u. Compare Section C, where one vowel replaces both.
In place of an ik, yaṇ occurs when an ac follows, within the domain of saṃhitā (close juncture). When "sudhī upāsyaḥ" stands [as the state to be operated on], by [the principle of] nearness (āntarya) in respect of place of articulation (sthāna), y is the substitute for ī. When "sudhy upāsyaḥ" has thereby arisen [the derivation proceeds].
iko yaṇaci — iko yaṇaci. "ikaḥ" is a genitive (ṣaṣṭhī). Hence, by the paribhāṣā "ṣaṣṭhī sthāneyogā" (A 1.1.49), the sense "in place of" (sthāne) is obtained. And "sthāna" has been said [earlier] to mean prasaṅga — the occasion [for a substitute], i.e., where the original would otherwise stand. Since it is impossible for one varṇa to be the locus (adhikaraṇa) of another varṇa [in a literal locative sense], "aci" is a sati-saptamī (a conditional locative, "when an ac is present"). By the paribhāṣā "tasminn iti nirdiṣṭe pūrvasya" (A 1.1.66), the sense "of what precedes, when an ac has been uttered with no other varṇa intervening" is obtained. And thus "when an ac follows (aci parataḥ)" results as the sense. "saṃhitāyām" is in force as a governing heading (adhikāra); and from that is obtained the absence of any temporal interval exceeding half a mātrā. This resultant meaning [Bhaṭṭoji] states with "ikaḥ sthāne" and so on. This [whole explanation] follows the older view that adheres to the literal wording of the sūtra.
In the Bhāṣya on the sūtra "saṃhitāyām," however, taking "aci" as a locative in the contactual sense of the locus (aupaśleṣika adhikaraṇa) — which is a form of proximity (sāmīpika) — and relying on [the paribhāṣā] "tasmin," the saṃhitā-adhikāra is rejected (pratyākhyāta) [as unnecessary]. For the Bhāṣya there runs thus: "This rule [saṃhitāyām] can be left unstated. How? The locus (adhikaraṇa) is of three kinds: pervasive (vyāpaka), contactual (aupaśleṣika), and domain-based (vaiṣayika). But what other connection can a sound have with a sound than contact (upaśleṣa)? [So] 'iko yaṇaci' means 'of the ik that is in contact with an ac.' There, even without mention of saṃhitā, [the operation] will occur precisely in saṃhitā." — upa means "in proximity," śleṣa means "connection," [so] upaśleṣa [is proximity-connection]; the locus constituted by that is aupaśleṣika, that is, proximity-based (sāmīpika). And thus it results as "of the ik standing in proximity to an ac." And proximity means the absence of any interval, both temporally and in respect of varṇa. And so, since in the absence of saṃhitā the said proximity is itself absent, the non-occurrence of yaṇ is established on that very ground; hence the saṃhitā-adhikāra need not be prescribed. Such is the purport of the Bhāṣya.
And thus, by parity of reasoning, in "tasminn iti nirdiṣṭe pūrvasya" (A 1.1.66) too the locative (saptamī) is in the contactual-locus (aupaśleṣika) sense. From that, the sense results: when the referent of a locative-ending word such as "aci" — something beginning with the vowel a — is uttered, the operation applies to the preceding [item] that is present [to it] by the relation of proximity. And the qualification "unintervened" (avyavahita) need not be supplied to "uttered," because that [immediacy] is already obtained precisely from the saptamī taken in the proximity-locus sense; for proximity there consists in the absence of interval both temporally and in respect of varṇa. And thus, there [in A 1.1.66], the syllable "nir" [in nirdiṣṭa] need not be taken separately for the sake of the sense of immediacy (nairantarya). This is made clear by Kaiyaṭa on the sūtra "snukramoḥ" and on the sūtra "tatra ca dīyate." The threefold nature of the locus will be clarified [later] in the kāraka section, at "ādhāro 'dhikaraṇam" (A 1.4.45).
sudhī — From the root "dhyai," in the sense of thinking (i.e., dhyāyati): with the kvip suffix, the y undergoes samprasāraṇa [becoming i]; then by pūrvarūpa [the single substitute in the form of the preceding vowel, for i + ā]; and by "halaḥ" (A 6.4.2) the vowel is lengthened — [yielding] the word dhī. Those who think well (suṣṭhu dhyāyanti) are sudhiyaḥ; or, those whose intellect (dhī) is excellent (su = śobhanā) are sudhiyaḥ. The analytical paraphrase (vigraha) is "sudhībhir upāsyaḥ" (to be worshipped by the wise). The compound is by "kartṛkaraṇe kṛtā bahulam" (A 2.1.32); and by "supo dhātuprātipadikayoḥ" (A 2.4.71) there is luk of the bhis-ending. When "sudhī upāsya" stands, the construal [with the sūtra] is that y is the substitute for ī. The secondary signification (lakṣaṇā) by which the pratyāhāras denote the individual sounds subsumed under what they denote is elaborated at the sūtra "nājjhalau" (A 1.1.10); to bring that out, ī has been given as the example [of an ik member].
Objection: Why should not v, r, l be [the substitutes] for ī, since they are all equally yaṇ, yaṇ-hood being non-differentiating? To this [Bhaṭṭoji] replies with "sthānata āntaryāt" (by nearness of place). Because of the shared palatal (tālu) place of articulation, in place of ī, by "sthāne 'ntaratamaḥ" (A 1.1.50), it is precisely y that occurs; not v, r, l, because they have different places of articulation. For this very reason, the Bhāṣya on the sūtra "yathāsaṃkhyam anudeśaḥ samānām" (A 1.3.10) [says]: "What is the example here [of yathāsaṃkhya]? iko yaṇaci — dadhy atra, madhv atra. This is not [a valid example]: it is established even by 'sthāne 'ntaratama' (A 1.1.50)." And the Bhāṣya on the sūtra "sthāne 'ntaratamaḥ" (A 1.1.50), conversely, says: "What is the example here? iko yaṇaci — dadhy atra. This is not [a valid example]: it is established even by saṃkhyātānudeśa" — meaning, by the yathāsaṃkhya-sūtra. [Each Bhāṣya passage thus refers its own would-be example to the other rule.]
Objection: Here, by the word "yaṇ," four sounds are taken — the non-nasal y, v, l, and r — because, the yaṇ being the item to be brought about (bhāvyamāna, i.e., the substitute), it does not take its homogeneous sounds (savarṇa); [whereas] even granting that the [phonetic] qualities (guṇa) are non-distinguishing [so that savarṇas would be included], y, v, l amount to six [each in nasal and non-nasal form] and r makes seven. But by the word "ik" sixty-six are taken. Being thus of unequal number, how can the yathāsaṃkhya-sūtra operate here? If [this is asked] — No: because, once unified under [the shared properties of] ik-hood, yaṇ-hood, and the like, they are equal [in the number of classes].
Objection: Since by the ṛ-varṇa and the ḷ-varṇa thirty [homogeneous sounds] each present themselves, there arises the liability (prasaṅga) of r as the substitute for the ḷ-varṇas and l as the substitute for the ṛ-varṇas; so the matter is not resolved by the yathāsaṃkhya-sūtra. If [this is objected] — listen: from the yathāsaṃkhya-sūtra it is obtained that "for what is delimited by ṛ-hood (ṛtva), r occurs; for what is delimited by ḷ-hood (ḷtva), l occurs." And the generic property ṛtva is not present in the ḷ-varṇas, nor is the generic property ḷtva present in the ṛ-varṇas. It is only by force of the rule of homogeneity (sāvarṇya) between the ṛ- and ḷ-varṇas that ṛtva is [figuratively] imposed upon the ḷ, and ḷtva upon the ṛ, for the sake of the operation. And thus, by taking the real (vāstava) ṛtva and ḷtva [rather than the imposed], the operation of yathāsaṃkhya here is unobstructed. But let this rest for now.
- textual The digital source carries several evident digitization glitches, followed here without silent emendation: 'प्रत्याह#आरेषु' (a stray # in pratyāhāreṣu); 'तिंरशत्' for triṃśat (thirty); 'निग्र्रहणं' for nir-grahaṇam. The pratīkas 'snukramoḥ' and 'tatra ca dīyate' (Kaiyaṭa citations) are left unnumbered, identification not being secure.
- textual In the dhī-lengthening step, the source reads 'halaś ca', a corruption of halaḥ (A 6.4.2, the rule that lengthens the samprasāraṇa vowel); the correct lemma halaḥ is given here.
- translator The unit turns on two competing analyses of how 'aci' and the saṃhitā-adhikāra deliver the environment, kept distinct here: (1) the older, wording-based view (saṃhitā as a separate adhikāra + immediacy derived from 'nir' of A 1.1.66); (2) the Mahābhāṣya view that reads 'aci' as an aupaśleṣika (contact) locative, from which proximity — hence saṃhitā and immediacy — follows without a separate saṃhitā-adhikāra. The translation does not adjudicate between them.