This page shows "Type C" Last Move problems.
The game here is to find diagrams with one player (conventionally Black) in check, such that the stipulation "Last move?" has a unique solution. Until 2007, checks were optional in Type C Last Move problems. Since then it was decided for simplicity to make checks compulsory. At the time of changeover, this only affected 2 problems (KxQ & PxQ=N)
We have solutions for all 60 Type C tasks, but in most cases we don't know if these are minimal.
One record (B×N) has been improved using the slightly controversial notion of Dead Reckoning (which became legal in 1997). It is a rare event for the underlying Laws of chess to change, and I believe worth celebrating. So it seems fairest and most fun to keep both the old and the new records. Thus the total number of problems listed here is 61.
Type A problems
Type B problems
Type D problems
Type F problems