Those workarounds will have to come into play, as the Nagano Prefectural Office of the DPJ has told sitting Minister of Infrastructure, Land, Transport and Tourism and Hata #1 Son Hata Yu'ichiro to forget about running for his father's House of Representatives seat.
It is hard to tell a sitting minister and son of a former prime minister to run for the seat, if he wants to run for it, as independent -- which he may do, despite having a nice seat in the House of Councillors, where he has rested his behind since 1999. (Link - J)
Credit to the party and its leader where credit is due.
Later- See Okumura Jun in comments on corrections to the above and the below.
* I am indebted to Okumura Jun for this characterization.
** The retirement of Watanabe and Hata will leave only one of the Seven Magistrates (