Yichudim (Unification) is a visualization exercise that helps the practitioner combine or unify the aspects of separate sephira on the Qabalistic Tree of Life into one principle. The exercise below is one that can be found in Practical Qabalah Magick by David Rankine and Sorita d’ Este.
“If you wanted to work with the combined energies of Tiphereth and Yesod (Sun and Moon), you would combine the letters of their respective Divine Names, and then vibrate and see the unified name.
However, the difficult part comes in seeing the images of the Hebrew, for the letters should be seen in the appropriate colours. To illustrate:
The respective Divine Names for Tiphereth and Yesod are Eloah (ALVH) and El Chi (ALChI). The letters are combined in turn, i.e. the first letter of Eloah, then the first letter of El Chi, then the second letter of each, to the last letters. As each extra letter is seen, the unified name is built up. This then gives a unified name of AALLVChHI
The letters are then vibrated in turn to give the whole unified name. This would be seen (right to left obviously) with the letters alternately gold and silver, with the letters taken from Eloah being gold, and those from El Chi being silver. The unified name would thus be seen as Aleph (gold), Aleph (silver), Lamed (gold), Lamed (silver), Vav (gold), Cheth (silver), Heh (gold), Yod (silver).”