Up and down
Up: towards the center of the board. See High.
Down: towards the edge. See Low.
Consequently,
- to descend means making a move towards the edge
- The central point on the board, Tengen is also referred to as heaven.
- A move like ago, attacking a stone more towards the center, is attacking from below.
On the other hand, the upper side of the board is the side closest to white.
To avoid this confusion some books use North, South, East, West. So, "the upper left corner of the board" simply becomes the NW corner.
See also know your lines, high or low, board geography.