Curriculum·S203 Chart Literacy and Evidence·about 31 min
The primitives
By the end of this lesson you can
- →State what a bar records and the three things it discards
- →Explain why a printed price is not necessarily a price that was available in size
- →Reconstruct what a bar can and cannot tell you about the sequence of events inside it
- →Choose a bar interval deliberately, knowing what each choice makes invisible
Sophomore · enrolled learners
This lesson opens with The wicks of 10 October 2025.
- What happened
- During the deleveraging event of 10 October 2025, more than $19B of leverage was liquidated in roughly a day. Of $9.89B in forced liquidations about 70 percent occurred inside 40 minutes, with a peak minute of $3.21B of which 93.5 percent was forced selling, while market makers withdrew and spreads widened. On a daily chart the entire episode appears as a single bar with a long lower shadow. That shadow records that trades occurred at those prices. It does not record that the depth available at them was a fraction of normal, that the sequence was overwhelmingly one-directional, or that most participants could not have transacted there in any meaningful size.
- The decision point
- The chart is not wrong. It is a summary, and a summary is defined by what it discards. A bar keeps four prices and a volume total and throws away the order of events, the depth at each level, and whether anybody could actually have transacted at the extremes. Every conclusion drawn from a chart is drawn from what survived that compression.
What you will be able to answer
- →What does a bar record, and what does it discard?
- →Is a printed price a price you could have got?
- →What can you not tell from a single bar?
- →How should you choose a bar interval?
Orientation and Year One are open: anyone can read them without an account. From Year Two onward the lessons are for enrolled learners, because progress through the later years only means anything if it is tracked against a record.
It is free. We do not sell the list and there is nothing to buy at the end of it.
Sources and review
- https://www.coindesk.com/research/market-spotlight-the-19-billion-liquidation-that-shook-crypto
- https://www.coingecko.com/learn/october-10-crypto-crash-explained
- https://www.newyorkfed.org/medialibrary/media/research/staff_reports/sr42.pdf
Confidence high·Volatility low·Reviewed 2026-08-05·Owner unassigned
Contested
S201-01 uses the 10 October 2025 event to teach order book depth. This lesson uses it to teach what a bar discards. Keep the split: if a revision starts explaining market maker withdrawal here, that content belongs in S201-01.
Whether extreme prints should be treated as valid data or filtered as outliers is a genuine methodological disagreement, and both practices are defensible. This lesson teaches learners to know which convention their tool uses rather than asserting one is correct.