古稀之年永不相忘
[gŭ xī zhī nián yŏng bù xiāng wàng]
'Gu Xi Zhi Nian Yong Bu Xiang Wang' roughly stands for 'Never Forget Even At The Age Of Rare Seniority'. Here, it implies remembering someone special with profound sentiment regardless of aging, vowing never to let precious memories fade as time goes by.