Writing down what can be checked, from inside China.
The part of China that is hard to see from outside: what a factory quote actually contains, what freight costs this month, what a market stall charges, what a hospital visit involves, and where the number in a headline came from. Six sections, one rule — if a number appears here, it came out of a script or a dataset that can be re-run. The AI tooling I test for a living is one of the six, not the theme of the site.
Latest
The AQI is a definition: China vs US breakpoints
One PM2.5 concentration, two index numbers. How China's HJ 633—2026 and the US breakpoints are built, and what GB 2626 and NIOSH require.
- China mobile bills: plans, top-up, autopay, suspension 2026-10-12
What a filed China Mobile plan actually lists, how a top-up reaches the account, what governs autopay, and the 60-day clock before a number closes.
- China's rail traffic: 44 times the US, on 69% of the track 2026-10-12
World Bank rail data to 2021: China carries 44 times America's passenger traffic on 69% of its route-km, and the two columns are not equally comparable.
- China's national sleep averages do not agree 2026-10-12
Chinese sources put average night sleep for the whole country between 6.85 and 7.84 hours, a year apart. The spread is sampling, instrument and definition.
- The documents a foreigner needs to work in China 2026-10-12
The work-permit notification, the Z visa and the work-type residence permit in the order the law puts them, plus the A, B and C tiers.
Notes
Sections
- AI and engineering 9 posts
Evaluations, task books and pipelines — plus the numbers worth keeping, from model prices to page weight.
- Supply chain 11 posts
What things cost to make and move: factory quotes, sourcing, freight rates, month by month.
- Life in China 20 posts
Everyday life here, sorted into what has been measured and what is only habit.
- Data and the world 8 posts
Open datasets, charted — global flows, and what they look like up close in one place.
- Health 4 posts
Sleep, food, teeth, sun, screening — the measurable part of looking after a body, written from the public guidance and never as advice.
- 海外华人 4 posts · 中文
中文栏目：生活成本、跨境比价、出入境流程，按年更新。