I have been told that that there are 600,000 letters in the Torah scroll, and I always understood this to be the case. However, I was recently made aware that if one actually counts the letters, one would find that there are just over half that amount of letters in a standard Torah scroll. How do we reconcile the number 600,000 with the more accurate count?
There are 304,800-plus letters in the Torah, but as you noted, we often hear of the 600,000 letters in the Torah. Several non-standard methods of counting are offered to arrive at the number 600,000.
One is given by Rabbi Shneur Zalman of Liadi, the founder of Chabad. The count includes vowel letters that are not included in the text, but are implied in the pronunciation of the word. If they were all to be written out, there would be many more letters in a Torah scroll.
Another view explains that the count of 304,800-plus letters includes only those that we see, black ink against white parchment. But there are also the letters in white against black. The heavenly, non-physical version of the Torah is described as black fire on white fire, and both the black and white are equally meaningful. The black are the letters we see, while the white, the inverse space between the black, are the letters we don't see. The count of 600,000 includes both the black and the white letters.
Knowing this, there's an interesting law about the writing in a Torah scroll that now makes a lot of sense: If any letter has no space around it, the entire Torah is invalid, even though all the letters are complete. According to what we've just said, this is easy to understand: Although the revealed black letters would be complete, a hidden white letter would be missing.
There's yet more significance to the idea of inverse letters. The 600,000 letters correspond to the 600,000 souls of Israel. Although there are many more than 600,000 Jews, there are 600,000 general souls which divide into the individual sparks that become each of our souls. Some are of the black letters; their place in Torah is clear. It holds their life and purpose. The black stands out in strong contrast to the surrounding space.
Those of the inverse, white letters may not see where they fit into Torah. The space around the letter isn't seen in its own right, it simply enables the black letter to be seen. Perhaps a soul is here to allow another to shine, but that soul is integral. If a black letter lacks the surrounding white letters, the entire scroll is invalid.