RHY.6:5.4 - Keep a sustained beat distinct from a silent beat

Reuse the two-beat instructions from RHY.5:5.4. The source supplies an onset at position 0 and either an endpoint at position 2 (A), or an endpoint at position 1 followed by a rest until position 2 (B). Units are beats; the interval ends at 2.

An onset-only target gives ta for both, losing the sustain/stop answer. Under Cha’s explicitly selected extension, translate A as ta–ah and B as ta (ta). Reading back through that convention recovers the required continuation or rest. A sustained syllable plus a beat gesture and an explicit endpoint can supply the same distinction without using this extension.

If the received source is only the untimed string ta, neither A nor B can be recovered uniquely. Keep the onset information and ask for duration only if the receiver must decide sustain versus silence. For an onset-count question, the available information already suffices.

The translation therefore ends in one of two useful results: a complete instruction for the supplied duration-sensitive source, or a qualified onset-only result for the underdetermined source. No experiment is needed to discover this information loss; the two constructed cases exhibit it.