Passage of the 15.4 trillion yen supplementary budget bill through the House of Representatives: May 13 (today)
When the supplementary budge bill will become law via the Article 60 budget override provision: June 12 (30 days later)
Date of the Tokyo Metropolitan District elections, the obsession of the New Komeitō: July 12
Date of the expiration of the term of the current House of Representatives: September 10
(Article 45 of the Constitution states that the term of a member of the House of Representatives shall be four years. The last House of Representatives election was held on September 11, 2005. )
Last day on which a House of Representatives election could be held: October 18
(The full 40 day maximum election period would extend to October 19. However, elections are always held on a Sunday.)
Question whose I do not the answer I do not know, though I wish I did, as it is becoming increasingly pertinent:
"While Article 54 of the Constitution mandates the maximum amount of time -- 40 days -- that can pass between a Diet dissolution and a House of Representatives election, what is the minimum amount of time, if such a statutory requirement exists?"
Time of the year when politicians do not want to be out campaigning due to furnace-like hot weather interrupted by occasional lighting storms: late July through August
Somewhere in all the above is a schedule for the runup to the House of Representatives election.
My best guess would have Francisco dissolving the Diet on Monday, August 31 with the election taking place on October 4.
Later - Thank you "Anonymous."
Note to self: avoid posting at insane hours of the night.
Even later - Okumura Jun provides the answer to my question in comments to his blog: the minimum number of days between the dissolution of a Diet and an election is twelve.
Now the bonus question: what law mandates the 12 day minimum?