Gargantua vs. gargantua

To make this post more understandable, I need to make a distinction between "Gargantua" and "gargantua". Whenever I use "Gargantua", I'm referring to the chess variant as a whole. Whenever I use "gargantua", I'm referring to the piece. Just to be crystal clear: a legal Gargantua move is a move made by any piece which is a legal Gargantua move, whereas a legal gargantua move is a move made by a gargantua which is a legal Gargantua move.

The Gargantua mate-in-one problems I've posted so far have all come from actual games I've played, but none of those games were Gargantua games; they were actually all standard chess games. What I did was to truncate the games if necessary, so that only legal Gargantua moves remained. For example, if a game was 20 moves long, but White made an illegal Gargantua move on move 10, I would truncate the game after 9 moves by each player. If Black made an illegal Gargantua move on move 10, I would truncate the game after White's 10th move.

A fair percentage of the time, the illegal Gargantua move would be due to the player who was to move having just been checkmated. Of course, by definition, any move attempted to be made by a player who has just been checkmated is illegal :-) Also, any move attempted to be made by a player who has just been put in check, and which does not get that player out of check, is illegal; another fair percentage of the time, the illegal Gargantua move would be due to this.

Since every standard chess game can be converted to a Gargantua game by means of this truncation process, it's easy to manufacture Gargantua games at will; however, these will not be particularly interesting games, since they won't have been played under the Gargantua rules.

The long and short of it is that I have a limitless supply of Gargantua mate-in-one problems, but very few of them (if any) could have come into being by players who were actually playing under the Gargantua rules.

Due to the lack of bona fide Gargantua games, I still don't know if Gargantua is a viable chess variant or not. I need chess players to check it out!

Puzzle of the day: how does Black mate in two here (or in three, if White gives up material)?

update: here's the solution