Showa
Japanese era running from 1926 to 1989, which was also the initial year of the current era, Heisei.
Not to be confused with Ito Showa the person.
At one point, around 1950, this nirensei opening in Go Seigen style was called the Showa fuseki .
Bill: By whom? Brief web searches in both English and Japanese turn up this as the only source.
Charles Go Review, Spring 1976, p.18. 'This combination of ,
and
is known as the "Showa fuseki", since it became very popular in the Showa period [...]". To be precise, then, it is the nirensei opening with
at one of the points a, that they talk about there.
Bill: Thanks, Charles! I have edited the diagram in accordance with the quote.
kb: Discussion of at /Discussion.