ADDING UNITS
These problems I perpetrated illustrate an original theme by Nicolas Dupont, and known as "habillement" in French. Essentially, the stipulation in almost all is "Add a unit: h#n". To be sound of course, there must be only one way that the unit could be added in order to allow a helpmate.
Should the diagram should be legal prior to the addition? I don't think it has to be (the addition takes place before the verification) but I would prefer it.
{A} & {B} show minimal examples. There is definitely some slicing and dicing of endgame tablebases that could produce other problems with this kind of stipulation. It could also be a novel way to present twins, particularly for problems that are otherwise slightly on the easy side.
Michel Caillaud proposed a tourney in which a given goal must be achieved both before and again (in a different way) after the addition: {C} to {F} were my submissions to this. Note that {D} is a direct mate not a helpmate. The results of Michel's tournament were published, but have been lost with the disappearance of pages from the France-Échecs site. I must find out what the results were...
| {A} France-Échecs |
{B} France-Échecs Dedicated to Samuel Lam |
{C} France-Échecs for Caillaud Tourney |
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| (1+1) Add a unit: h#3.5 | (1+1) Add a unit: h#3.5 | (10+12) h#2.0 b) Add a unit | ||
| {D} France-Échecs for Caillaud Tourney |
{E} France-Échecs for Caillaud Tourney |
{F} France-Échecs for Caillaud Tourney |
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| (15+3) #1 b) Add a unit. | (11+12) h#2 b) Add a unit c) To (b) add another unit. | (13+11) h#2 b) Add a unit c) To (b) add another unit. |