What is a break of structure (BOS) in trading?
Updated Nov 9, 2026 · 3 min read
A break of structure is a close beyond the last swing high or low in the trend's direction. Definition, BOS vs change of character, and 4-hour structure on BTC, ETH, SOL and HYPE on Nov 9, 2026.
What is a break of structure? A break of structure (BOS) is a candle close beyond the most recent swing high in an uptrend, or below the most recent swing low in a downtrend. It says the trend is continuing. The first close through a swing in the opposite direction is called a change of character (CHoCH), the first sign the trend may be turning.
Key takeaways
- A swing high is a candle with lower highs on both sides; a swing low has higher lows on both sides.
- Uptrend: higher highs and higher lows. A close above the last swing high is a bullish BOS.
- Downtrend: lower lows and lower highs. A close below the last swing low is a bearish BOS.
- Use closes, not wicks. A wick through a level that closes back inside is often a liquidity grab, not a break.
4-hour market structure on Hyperliquid, Nov 9, 2026
Swings are marked with two candles on each side (a five-candle fractal) on the 4-hour chart. The last column shows the most recent close through a prior swing.
| Market | Last swing high (4h) | Last swing low (4h) | Price | Last break of structure |
|---|---|---|---|---|
| BTC | $76,173 (Nov 8) | $73,457 (Nov 8) | $74,118 | close below swing low at $75,549, Nov 8 20:00 UTC |
| ETH | $2,245 (Nov 8) | $2,058 (Nov 8) | $2,109 | close below swing low at $2,223, Nov 8 20:00 UTC |
| SOL | $90.00 (Nov 8) | $88.69 (Nov 7) | $85.92 | close below swing low at $88.69, Nov 8 20:00 UTC |
| HYPE | $78.05 (Nov 8) | $76.69 (Nov 7) | $72.91 | close below swing low at $76.69, Nov 8 20:00 UTC |
All four last broke structure to the downside, the shape of a downtrend on the 4-hour chart.
BOS vs change of character
| Break of structure (BOS) | Change of character (CHoCH) | |
|---|---|---|
| What breaks | The last swing in the trend’s direction | The last swing against the trend |
| What it suggests | The trend continues | The trend may be turning |
| How traders use it | Add or enter with the trend on a pullback | Tighten stops, take profit or wait for confirmation |
Trading structure on Senpi
Describe the rule in a sentence to your Senpi agent, in the app or from Claude, ChatGPT or another AI app through the connectors. Senpi shows the rules back to you, then runs them in a separate strategy wallet with the stop attached from the first fill.
- Viper, SMC/ICT structure trader: enters on a break of structure or a change of character; the Dynamic Stop-Loss handles every exit.
- Ibis, trend and range regime-switcher: checks whether a market is trending or ranging before choosing a breakout or a fade.
What is the difference between BOS and CHoCH?
A break of structure is a close past the last swing in the direction of the trend, so the trend continues. A change of character is the first close past a swing against the trend, the first sign it may be reversing.
Should a break of structure be confirmed by a close?
Most traders require a candle close beyond the swing, not just a wick. A wick that pokes through and closes back inside is often a stop run rather than a real break.
Which timeframe should I use for market structure?
Use a higher timeframe (4-hour or daily) for the trend and a lower one (15-minute or 1-hour) to time entries. Structure on very short timeframes breaks constantly and carries little information.
Is a break of structure a buy signal?
Not on its own. It tells you which way the trend is pointing. Most rules wait for a pullback after the break, into a fair value gap or the broken level, before entering, with a stop beyond the last opposite swing.
Let an agent watch market structure for you
Describe your structure rules in a sentence. Senpi runs them around the clock with the stop attached.
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