Last Remaining Cell
Last Remaining Cell is the positional single: in one row, column, or box, a particular digit has only one possible cell — the move commonly called a Hidden Single.
What is Last Remaining Cell?
Choose one digit in one row, column, or box and consider all of its remaining positions. If every position but one has been ruled out by digits already placed in the intersecting houses, the digit must occupy the remaining cell. This differs from Last Free Cell, which requires a house with eight placed digits.
Finding the cell
Choose one digit in a house where it is missing, then crosshatch the positions that are already filled or blocked by that digit in the intersecting rows, columns, and boxes. When eight positions are excluded, the ninth is the Last Remaining Cell.
Apply both sets of exclusions
Eight positions for the digit are already filled or blocked in the house, so the ninth is the only cell it can go in. Write it in — that's the last remaining cell.