Setsuko (節子) combines setsu (season, virtue, integrity) and ko (child) — "gentle child" or "child of integrity."
Setsuko Hara (1920-2015) was the iconic Japanese actress of Ozu's films.
Setsuko does not currently appear in the US Social Security Administration's top 1,000 girls' names, so we don't publish a US rank or birth count for it. That says nothing about the name's standing elsewhere in the world — only that it sits outside the ranked US data we rely on.
In Pythagorean numerology the letters of Setsuko reduce to 2, The Peacemaker. This is a traditional interpretive system, not a factual claim about the name.