A change of character, or CHoCH, is the first time price breaks structure against the prevailing trend. In an uptrend it is the first lower low that breaks a previous higher low; in a downtrend it is the first higher high that breaks a previous lower high. It is the earliest structural hint of a possible reversal.
CHoCH versus BOS
The difference is direction. A BOS breaks with the trend and confirms continuation; a CHoCH breaks against the trend and warns of change. Reading them together lets you follow a trend and also be alerted the moment its character shifts.
How to use it carefully
A CHoCH is a warning, not a guarantee — trends often pause and resume. Treat it as a signal to tighten risk and to stop looking for trend-continuation entries, but wait for further confirmation (such as a new opposing structure) before betting on a full reversal.
A change of character is the first crack in a trend — an early warning to protect open trades, not proof of a reversal.