[Retros] Task

[Nicolas.Dupont at math.univ-lille1.fr]

Dear retro friends,

In the web-site "France-Echecs", I proposed the following problem :
Construct the shortest possible exact proof game ending by a check-mate
given by a piece returning at home.

Here are our records, the 2 sections depending on whether or not some
piece is captured during the game  :

Knight without capture : 6 moves (Itamar Faybish)
Knight with capture : not least

Bishop without capture : 6.5 moves (Itamar Faybish)
Bishop with capture : not least

Rook without capture : 9 moves (Itamar Faybish)
Rook with capture : 6 moves (Joachim Iglesias)

Queen without capture : 6 moves  (Joachim Iglesias)
Queen with capture : not least

King without capture : 6 moves  (Nicolas Dupont)
King with capture : not least

Is it possible to beat some of them ?

Best wishes,

Nicolas Dupont.