Placing the decan
Faces are ten degree divisions, three to a sign and thirty six around the ecliptic. This one begins where the Sun passes ten degrees of Scorpio and ends at twenty.
In calendar terms it usually runs from about 3 November to about 13 November. Those dates should be read as approximate. The tropical year is not a whole number of days, so the boundary drifts by up to a day and a half between years, and your time of birth moves it again. Somebody born on the third or the thirteenth of the month is genuinely on a line and cannot settle it from a table.
The Sun by one count, Pisces by the other
The Chaldean order runs a fixed loop of Mars, Sun, Venus, Mercury, Moon, Saturn and Jupiter, begun at zero degrees of Aries and continued without a break around the wheel. The twenty third face comes up as the Sun.
The triplicity scheme divides a sign's faces among the signs of the same element, in sequence. Scorpio's water decans belong to Scorpio, then Pisces, then Cancer, so this middle face is the Pisces one. Modern sources give it Neptune as Pisces' contemporary ruler, with Jupiter behind it in older texts.
The Sun and Neptune pull in opposite directions, one towards definition and the other away from it, so the choice of scheme changes the reading substantially rather than shading it. This is the sort of decan where an article that names a ruler without naming a method should be treated with caution.
What the tradition makes of the blend
The Pisces colouring is read as Scorpio without hard edges. The sign's usual watchfulness is assumed to be present, but this face is described as absorbing an atmosphere rather than investigating it, and as slower to draw a line between itself and other people. Traditional writing associates it with imagination applied to motive, which can mean unusual accuracy about what someone is feeling and equally can mean a conclusion reached before the evidence supports it.
The Chaldean Sun is read as adding visibility to material that Scorpio would otherwise keep back. Older texts link a solar face to matters becoming public, to reputation and to a position that has to be held openly. Set against a Piscean background that would rather stay indistinct, it is generally interpreted as a pull between concealment and disclosure rather than a settled disposition.
These readings apply to any placement in the range, not only the Sun. The Ascendant and the Moon are read by decan routinely, and on a water Moon this face is often given more weight than it would carry on a Sun. Decans come down from Egyptian star lists that predate the twelve signs in their present form, so the technique has a real history, but it remains a refinement layered on a chart rather than a foundation.
The reason to calculate
A decan boundary is a degree of longitude. The Sun moves about one degree a day, so a birthday at either end of the range can fall on either side depending on the year and the hour.
The check above computes the Sun's actual position from your birth date and reports the degree together with the ruler each scheme gives it. For anyone born near an edge that is the only way to know, and a printed range will occasionally be wrong.
It also names the decan on either side, so a close result is easy to interpret.
Questions people ask about this
What dates does the second decan of Scorpio cover?
Broadly 3 to 13 November. Both edges move by up to a day and a half between years, so a birthday at either end needs the solar degree calculated rather than looked up in a table.
Which ruler applies here, the Sun or Neptune?
The Sun under the Chaldean order and Neptune, or Jupiter in older practice, under the triplicity scheme via Pisces. They give quite different readings, which is why this page names both instead of choosing one.
Does the Pisces face make a Scorpio gentler?
The tradition reads it as less guarded rather than gentler, which is not the same thing. It describes where the sign is porous, and the rest of the chart decides how that shows.
Why do sources disagree about this decan?
Because they are usually working from different schemes without saying so. Once you know whether a writer counts in Chaldean order or by triplicity, apparently contradictory descriptions become straightforward to reconcile.
Can I read a decan for my Moon or Ascendant?
Yes. Every placement in a chart sits in one of the thirty six decans, and many practitioners find the technique more informative on the Moon and the Ascendant than on the Sun.
Are decans a modern invention?
No. They originate in Egyptian star lists used for telling the time at night and were given planetary rulers in the Hellenistic period. The interpretations circulating today are newer than the framework itself.