What's said to have funded the Great Wall (4)

I believe the answer is:
keno
(Other definitions for keno that I've seen before include "gambler's choice" , "A bingo-like game" , "gambling game" , "2 8 [CASINO GAME]" , "game of chance" .)
I believe the answer is:
keno
(Other definitions for keno that I've seen before include "gambler's choice" , "A bingo-like game" , "gambling game" , "2 8 [CASINO GAME]" , "game of chance" .)