Another source of info for Elliott:
All diagonals consist of 5 waves
Diagonals can be ‘leading’ or ‘ending’ diagonals, depending on whether they form at the start or end of a trend. Diagonals therefore can only form in the positions of wave 1 (leading) or 5 (ending) of an impulse, or the positions of wave A (leading) or C (ending) of a zigzag.
Within an ending diagonal, all 5 waves must be zigzags (simple-, double-, and triple-zigzags are all valid)
Within a leading diagonal, at least waves 2 and 4 must be zigzags (simple-, double-, and triple-zigzags are all valid). Waves 1, 3 and 5 can be impulses or zigzags. (If 1, 3, and 5 are impulses, be aware that it could easily be a 1-2, 1-2, 1-2 sequence instead of a diagonal)
Wave 2 must not retrace more than 100% of wave 1
Wave 4 must overlap with wave 1(please note that opinions differ over this rule. There are some Elliott Wave researchers who believe that ending and leading diagonals can be valid without wave 4 needing to move into territory of wave 1, although they still consider it unusual)
Wave 4 never moves beyond the end of wave 2
Leading and expanding diagonals must not have a truncated 5th wave.
Contracting diagonals always have a shorter wave 3 than wave 1 (in terms of percentage gain/loss)
Contracting diagonals always have a shorter wave 5 than wave 3 (in terms of percentage gain/loss)
Contracting diagonals always have a shorter wave 4 than wave 2 (in terms of percentage gain/loss)
Expanding diagonals always have a longer wave 3 than wave 1 (in terms of percentage gain/loss)
Expanding diagonals always have a longer wave 5 than wave 3 (in terms of percentage gain/loss)
Expanding diagonals always have a longer wave 4 than wave 2 (in terms of percentage gain/loss)
Guidelines:
Contracting diagonals form within two converging trend lines (contracting wedge)
Contracting diagonals can overshoot its trend line during wave 5 (called throw-over) and still be valid as long as wave 5 remains smaller than wave 3
Contracting ending diagonals can also undershoot its trend line during wave 5 (truncation).
Contracting ending diagonals should always show a corresponding decrease in momentum as they progress towards their culmination. Many small candles that take a lot of time to gain further ground is a good sign that an ending diagonal is indeed occurring. Conversely, strong big candles within a potential diagonal formation should be a warning sign that you are probably witnessing a 1-2, 1-2, 1-2 extension of the trend, and therefore not an ending diagonal.
Expanding diagonals form within two diverging trend lines (expanding wedge). They are more rare than contracting diagonals
Wave 2 and 4 of any diagonal very often retrace their wave 1 and 3 much deeper when compared to wave 2 and 4 of impulses
The internal zigzags of any diagonal can sometimes subdivide into more complex double or triple zigzags
Any diagonal can begin to be confirmed with higher certainty once wave 4 is close to being complete
Diagonals are more rare in general (although they do occur quite frequently within sub-waves of very small wave degrees that are visible on timescales of M15 and lower)
If wave 1 is a leading diagonal, wave 3 is usually extended.
A place to watch out for potential expanding leading diagonals is at the start of stock market declines (due to the opposing forces that are in play during this transitional period). Diagonals occur because of transitory forces of trend changes act against each other
Ending diagonals are followed by a strong reversal most of the time