当...的时候，往往就是...
Reach for this when you want to make a pointed observation about timing — the moment X happens is usually the exact moment Y is also true. It's an aphoristic, reflective structure, common in essays, investing commentary, and editorial writing where the speaker is naming a pattern they've seen play out. The 往往 ('often/tend to') keeps the claim from sounding absolute, and 就是 sharpens the link so the two moments feel like the same moment, not just correlated.
Structure
当 [CONDITION] 的时候，往往就是 [CONSEQUENCE] 的时候
dāng... de shíhòu, wǎngwǎng jiùshì... de shíhòu
How to Think About It
Two clocks pointing at the same hour. The first clause names a visible moment (everyone is buying, everyone agrees, the crowd is loudest) and 往往就是 says: that exact tick on the clock is also when the hidden thing kicks in. The power is in 就是 — it collapses the two moments into one. Replace 就是 with 也是 and you get correlation; with 就是 you get identity.
Examples
当所有人都看好一家公司的时候，往往就是它最贵的时候。
Dāng suǒyǒu rén dōu kànhǎo yī jiā gōngsī de shíhòu, wǎngwǎng jiùshì tā zuì guì de shíhòu.
When everyone is bullish on a company, that's usually exactly when it's most expensive.
当你觉得自己最懂的时候，往往就是你最容易犯错的时候。
Dāng nǐ juéde zìjǐ zuì dǒng de shíhòu, wǎngwǎng jiùshì nǐ zuì róngyì fàncuò de shíhòu.
When you feel like you understand the most, that's usually exactly when you're most likely to make mistakes.
当一个市场最热的时候，往往就是它最危险的时候。
Dāng yī gè shìchǎng zuì rè de shíhòu, wǎngwǎng jiùshì tā zuì wēixiǎn de shíhòu.
When a market is at its hottest, that's usually exactly when it's most dangerous.
Common Mistake
Learners forget the second 的时候 because English drops it ('that's when it's most dangerous'). In Chinese, both halves usually take 的时候 so the parallel structure lands; without it the sentence feels truncated.
当大家都买的时候，往往就是最危险。
当大家都买的时候，往往就是最危险的时候。
Don't Confuse With
一...就...
Pure sequence — 'as soon as X, then Y.' No reflection, no aphorism. Use 一...就... for cause-and-effect timing, 当...的时候，往往就是... when you're stating a recurring truth.
每当...的时候
'Every time X happens' — habitual, no claim about what Y is. Use 每当 to describe routine; use 当...往往就是 to point out a pattern with insight.
只要...就...
Conditional, not temporal. 只要 says 'as long as X is true, Y follows.' This pattern says 'at the moment X happens, Y is also happening' — same moment, not cause and effect.
Practice
Fill in: 当大家都买的时候，___就是最危险的时候。
Show answer
往往
Fill in: 当你最自信的___，往往就是你最容易犯错的时候。
Show answer
时候
Arrange: 的时候 / 当 / 最贵 / 往往就是 / 的时候 / 所有人都买
Show answer
当所有人都买的时候，往往就是最贵的时候。
Translate: When everyone agrees, that's usually exactly when the answer is wrong.
Show answer
当所有人都同意的时候，往往就是答案错了的时候。
Write one sentence using 当...的时候，往往就是... to describe a pattern you've noticed.
Show answer
当一个东西很便宜的时候，往往就是没人想要的时候。
Hear It in Real Episodes
This pattern appears in 1 Fluentide episode: