一马平川

flat land one could gallop straight across (idiom); wide expanse of flat country

one / single / a (article) / as soon as / entire; whole; all; throughout / "one" radical in Chinese characters (Kangxi radical 1) / also pr. [yao1] for greater clarity when spelling out numbers digit by digit

surname Ma / abbr. for Malaysia 馬來西亞|马来西亚[Ma3 lai2 xi1 ya4]

horse / CL:匹[pi3] / horse or cavalry piece in Chinese chess / knight in Western chess

surname Ping

flat / level / equal / to tie (make the same score) / to draw (score) / calm / peaceful / abbr. for 平聲|平声[ping2 sheng1]

Pingchuan district of Baiyin city 白銀市|白银市[Bai2 yin2 shi4], Gansu

an expanse of flat land

abbr. for Sichuan Province 四川[Si4 chuan1] in southwest China

(bound form) river / creek / plain / an area of level country