If we look at each month as a ten sets of three, we discover a pattern that repeats itself. The number ten always corresponds to the ten sefiros, so we can unearth a lot of information if we look at it through that lens.
The month looks as follows:
Day of month
As Malchus is always the mochin of the following set, it is an overlay into the next month, and therefore is sometimes counted as the first of the next month. This is the concept of Keser-Malchus. Something else that comes out of this is that the beginning of the next month, really the first nine days, which are Keser-Chochmah-Binah, are really a continuation of the previous month. The koach of the previous month is then born into reality when we get to Chesed of the following month, which is the tenth.
With this information, we get an interesting insight into Chanukah and the connection to Yosef, whose story is always read around Chanukah. Chanukah begins on the 25th of the month, which, as we noted, is the beginning of the sefirah of Yesod. It is the culmination of the month, which, as we spoke about last year, is really the completion of Succos, as well. It is a funneling of all of the spiritual power that has been going on.
That is the concept of Yosef, who is the focused power of Yaakov in the lower spiritual realm, as represented by his sons. Yosef is Yaakov in the lower realm (אלה תולדות יעקב יוסף). Yosef also extends further, as does Chanukah. Yosef's two sons become tribes of their own. Chanukah is the only chag that crosses the month border into the next month. This passes through Rosh Chodesh, which is when the moon, which reflects the light of the sun, is completely invisible, coming into union with the Sun. (The moon and Sun are in the same location on the horizon at the beginning of the month.)
Yosef's conception took place on the ultimate Rosh Chodesh - Rosh Hashana. This day is intimately connected to the concept of the Tzaddik and the concept of Yesod, as represented by Yosef, who was the Tzaddik Yesod olam. On Rosh Hashana, the world completely nullifies itself by giving homage to the King of kings who created it all. That complete hisbatlus is the character of the true Tzaddik. This is the light of Chanukah.