Short answer

You will see retracements in Renko charts when price reversals occur because the system recalculates bricks within your current selected chart time frame.

How far can retracement happen?

The retracement can occur all the way back to any brick within your current selected chart time frame. However, bricks from previous periods remain permanent and fixed. Your Renko chart continuously recalculates bricks as new price data arrives during the selected chart period. This means:

Bricks within the current time frame adjust based on incoming price movements

Only completed periods become permanent

The chart updates dynamically until the current period closes

What this means for your analysis

Until your selected chart period completes, you should expect the bricks within that period to change as new data comes in. The system plots Renko bricks according to the most current price information available.