plank, board, plate, stage
板 centers on a flat, rigid piece of material: a plank, board, or plate. The stage sense extends this to a flat raised platform.
板 combines 木 (tree, wood) with 反, which likely contributes the sound and may suggest something flat or spread out. Together they indicate a flat piece of wood.
A tree 木 turned into a flat, spread-out 反 plank: 板 is a wooden board or plate.
For ハン, imagine a hand placing a plank: hand -> ハン, and the wooden board is set in place.
board; plank
bulletin board; display board; notice board
signboard; sign; billboard; hoarding; doorplate
iron plate; steel plate
leaving the mound; being knocked out
white dragon tile
taking the mound; pitching a game
(circuit) board; substrate
wooden bridge (with planks)
deck (of a ship)
blackboard
chopping board; cutting board
platelet; thrombocyte
pretty girl who attracts customers to come inside a shop
steel sheet; steel plate
being stuck between a rock and a hard place; being in a dilemma; being torn between conflicting demands
chef (esp. of high-end Japanese cuisine); cook
veneer board; plywood
sheet metal; metal plate
floorboard