This page shows **"Type D" Last Move** problems.

The game is to find diagrams such that the stipulation **"Last move?
Duplex."**
has a unique solution (i.e. the last move is determined if White just moved, and
again the last move is determined if Black just moved.) The diagram is necessarily
check-free.

There are basically 60 different kinds of last move. Therefore, there are in principle 60*59/2 = 1770 possible Type D tasks. This is far too many to be interesting, so different composers have focused on a different sub-themes, e.g.:

- Type DD problems: the White & Black last moves have the same nature (e.g. King move without capture.)
- The number of units used is =< 12. (8 units is the minimum right now.)
- Showing that each last move of the 60 possibilities does appear as part of some pair. (All have been found now, except e.p., which is probably impossible, even using Dead Reckoning.)

Type A problems Type B problems Type C problems Type F problems