40
卌 represents the number forty, a specific numeral value.
卌 is a numeral character for forty, likely derived from a combination of four tens (十 repeated four times) compressed into a single character. The exact historical development is uncertain.
The shape looks like four vertical strokes (representing four tens) bound together by a horizontal line, making forty.
For シュウ, imagine a shoe store having a sale: all shoes are forty percent off. Shoe -> シュウ, and the discount is forty.