Unknown time: leap-day adult stays three-pillar

Many readers do not know their birth time. Records get lost, families disagree, and in some countries the time was simply never written down. This case shows what the calculator does in that situation, using a leap-day date as a memorable example.

The rule is that the hour pillar is withheld rather than guessed. Year, month, and day pillars are published as a date-level reference, but they are not universally final when the missing time could move a solar-term or true-solar day boundary. The hour pillar, the exact true solar time, the exact correction, and the exact Luck Pillar start are all suppressed, because producing them would require a birth time that nobody supplied.

Internally the engine does use a noon placeholder to obtain a date-level reference. That placeholder is deliberately kept out of the public output. A chart that quietly presented a noon-derived hour pillar as if the reader had given a time would be inventing information, and the wrong hour pillar is more misleading than an absent one.

The leap-day date is not incidental. 29 February is a date that some systems handle awkwardly, and pinning one here confirms that the date arithmetic survives it. The case therefore does double duty: it demonstrates the unknown-time disclosure contract and it guards a calendar edge that has nothing to do with unknown times at all.