DIY Tatami Bed Frame

Stand six 2-by-2-by-6 inch wood blocks up on their ends and set a 3/4-by-43-by-79 inch plywood sheet on top of them. Spread the wood blocks out so that one is in each corner of the sheet with its outside edges flush with the outside edges of the plywood, and the other two blocks are centered along the longer sides of the plywood sheet. Set the outside edge of the two centered blocks even with the outside edge of the plywood sheet on that side.

Drill two evenly spaced holes down through the plywood sheet and into each block. Attach the blocks to the plywood sheet with 2-inch wood screws tightly fastened.

Arrange two 1-by-3-by-43 inch boards parallel to each other, about six feet apart. Set two 1-by-3-by-77 inch boards between them, perpendicular to the shorter boards but parallel to each other so that the four boards form a rectangular frame with the shorter boards on either side of the longer boards. Drill two evenly spaced holes through the larger outer surface of each of the smaller boards and into the end of each of the longer boards. Attach the boards together with 2-inch wood screws.

Flip the plywood sheet upside down and set it on the four boards, arranging the frame so that it is evenly spaced on the rectangular board arrangement. Predrill evenly spaced holes every 12 inches around the outside edge of the plywood sheet and into the boards underneath. Attach the boards with 2-inch wood screws.

Flip the bed frame over and place a 4-inch foam mattress within it. Top with a tatami mat.