在八字与紫微中，大运（Da Yun）指因人而异的十年一换的人生阶段，流年（Annual cycle）指每一年的干支。它们由命盘出生时间推算，用于观察不同人生阶段的节奏与主题。
Da Yun are personal 10-year phases; annual cycles are each year's stems & branches. They help observe the rhythm and themes of different life stages.
起运年龄由出生时间与节气推算（俗称"几岁起运"）。每到交运年份，命盘的气场切换，传统上认为这段时间行动宜谨慎、做重大决定前多番考量——这是经验提醒，而非确数预言。
The age at which Da Yun begins is computed from your birth time relative to seasonal festivals. At each transition, tradition advises caution and careful deliberation — an experiential caution, not a fixed prophecy.
同一大运，对"喜用神"的人可能顺遂，对"忌神"的人可能吃力。所以解读需要回到个人命盘，不能概而论之。这也是为什么同一句话对不同人意义不同。
The same period may feel smooth for a favorable element but harder for an unfavorable one. Contextual reading matters — never one-size-fits-all.