The Tenkan Sen, also known as the Turning or Conversion line, is a moving average of the highest high and lowest low over the last 9 trading days.  It is primarily used to measure short-term momentum and is interpreted in the same manner as a short-term moving average.

A steeply angled Tenkan Sen indicates a sharp recent price change or strong momentum, while a flatter Tenkan Sen indicates low or no momentum.  The price breaching the Tenkan Sen may give an early indication of a trend change.

The Tenkan Sen is generally used in combination with the Kijun Sen to suggest probabilities of future momentum.

Example: Tenkan Sen providing support, with a trend change following after it is breached.

The Kijun Sen, also known as the Standard or Base line, is a moving average of the highest high and lowest low over the last 26 trading days.

As with the Tenkan Sen, the Kijun Sen is primarily used to measure momentum, however because of its longer time period it is a more reliable indicator of trend.  A flatter Kijun Sen indicates a range bound price, while an inclined line indicates a trend, with the angle of the line showing the momentum of the trend.

The Kijun Sen is generally used in combination with the Tenkan Sen to suggest probabilities of future momentum.

Example: Kijun Sen indicating bearish trend, until it flattens indicating a range bound price.

The Senkou Span A, also known as the 1st leading line, is a moving average of the Tenkan Sen and Kijun Sen and is plotted 26 trading days ahead, i.e. into the future.  It is primarily used in combination with the Senkou Span B to form the Kumo (cloud), to indicate probable future support and resistance levels.  

As price tends to respect prior support and resistance levels, time-shifting this line forward gives a visual representation of how the price on a date relates to support and resistance from 26 trading days prior.

The trend is deemed to be bearish when the Senkou Span A is below the Senkou Span B and bullish when it is above.

Example: Senkou Span A providing resistance.

The Senkou Span B, also known as the 2nd leading line, is a moving average of the highest high and lowest low over the last 52 trading days is plotted 26 trading days ahead, i.e. into the future.  As such it is the longest term representation of equilibrium in the Ichimoku system.  It is primarily used in combination with the Senkou Span A to form the Kumo (cloud), to indicate probable future support and resistance levels.

As price tends to respect prior support and resistance levels, time-shifting this line forward gives a visual representation of how the price on a date relates to support and resistance from 52 trading days prior.

The trend is deemed to be bearish when the Senkou Span A is below the Senkou Span B and bullish when it is above.

Example: Senkou Span B providing support.

The Kumo, also known as the Cloud, is the area between the Senkou Span A and the Senkou Span B, and is at the center of the Ichimoku system.

The Kumo is primarily used to indicate probable future support and resistance levels, with the top of the Kumo indicating the first level of support and the bottom the second level when the price is above the Kumo.  Conversely, the bottom of the Kumo indicates the first level of resistance and the top the second level when the price is below the Kumo.

A price above the Kumo indicates a bullish trend and a price below indicates a bearish one, while price within the Kumo indicates a potentially trend-less or range-bound situation.

The thickness of the Kumo shows the level of historical volatility, as well as the strength of support or resistance.  A thicker Kumo shows a greater the level of historical volatility and support or resistance, and vice-versa.

Example: price range-bound within the Kumo.

The Chikou Span, also known as the Lagging line, is the closing price plotted 26 trading days behind, i.e. into the past, providing an at-a-glance view of how the price compares to that 26 days ago.

The trend is deemed to be upward when the Chikou Span is above the closing prices and downward when it is below them.  The relationship is not always clear when looking at historical data, but becomes more obvious when looking at current charts.

The Chikou Span is also considered of use for confirmation of trends, momentum, and support and resistance levels highlighted by the other Ichimoku elements.

Example: Chikou Span indicating a bullish trend.