All year, the same gap
Neither Tokyo nor Singapore changes its clocks, so the gap is the same on every date.
12:00 PM Wednesday 15 Jul in Tokyo is 11:00 AM Wednesday 15 Jul in Singapore (SGT, 1 h behind).
Why daylight saving conversions need a date explains skipped and repeated clock readings. The rules here come from the browser’s time zone data and can lag a government change.