The Chikou span is a component of the Ichimoku Kinko Hyo indicator, also referred to as the Ichimoku Cloud. It was developed by a Japanese journalist in 1969. It's a technical indicator that plots the closing prices of 26 periods. It's generally not used on its own to predict trade signals.

The Ichimoku Cloud indicator can be used in any time frame, and there is no "best" one. It all depends on what type of trader you are. Day traders might prefer to use the Ichimoku on the M5 or M15 chart to help them identify the trend and/or get entry and exit signals.

Chikou spans are designed to allow traders to visualize the relationship between current and prior trends. A Chikou span that is currently trading above where prices were 26 periods ago indicates a present uptrend for the asset. Current trading below past price trends indicates a downtrend.

The effectiveness of Ichimoku Cloud is often debated among traders, with some studies suggesting a success rate of around 40% in bullish setups. However, it's important to note that in bearish scenarios, the strategy may perform less effectively, with potential losses averaging around -25%.