Tuìxiū zhīhòu tā de shūfǎ yùfā jīngjìn, zhēnshì shuāngyèhóngyú'èryuèhuā.
His calligraphy has only improved since retirement — truly, 'frost-touched leaves are redder than spring blossoms.'
Tips
history
Closing line of Du Mu's (杜牧, late Tang) 《山行》 ('Walking the Mountains'): 远上寒山石径斜，白云生处有人家。停车坐爱枫林晚，霜叶红于二月花 — 'Far up the cold mountain the stone path slants; where white clouds rise there are homes. I stop the carriage just to love the maple wood at dusk — its frost-touched leaves are redder than spring flowers.'
usage
Often applied metaphorically to older people whose achievements come in their later years, or to late-career excellence. 于 here functions as 'than' in comparative construction (redder than).
