[Retros] ELM Records

[Otto Janko]

Dear Community,

Definition of ELM problems according to the Retro Corner: 

»For each move type, e.g. plain moves, capturing moves, etc., find a
twinning a) white to move, b) black to move a legal last move of the "same
nature".«

- Are a checking last move and a non-checking last move 
  of the »same nature«?

- Are a mating last move and a non-mating last move 
  of the »same nature«?

Is it worth to introduce checking/mating moves as new sub-category? If yes,
is it worth to distiguish between direct check/mate and uncovered
check/mate?

~ÔttÔ~