Thank you for bringing this to our attention. I must have read about this in my youth, because it is detailed in R. C. Bell’s Board and Table Games of All Civilizations, which I read about 45 years ago, but I don’t remember and never connected it with Go. First let me get a few minor points out of the way. Edward Falkner’s Games Ancient and Oriental lists two earlier, European books that mention Go: Semedo’s Relacione della Grande Monachia [sic] della China (1643) and Trigantius’ De Christiana Expeditione apud Sinas (1616). Also, this game is obviously Hnefatafl, but has been given the name Alea Evangelii (Game of the Evangelists) by the manuscript’s author in keeping with his Biblical interpretation. This highlights what I find to be the most interesting aspect of this game: it is a splendid example of the Christianizing of pagan cultural elements (most conspicuously seen, perhaps, in Latin America). Wikipedia notes another example involving a tafl game associated with the Gospels as appearing in Cormac’s Glossary (900 A.D.). The CCC Ms. 122 is actually a 12th-century document (c. 1140), which is a copy of a 10th-century document. This fits very nicely with the early missionary efforts in Scandinavia, which began in the 8th century and achieved the establishment of archdioceses in the 12th century.
Now to get down to the main business. I suppose I should say from the outset that I don’t mean to be a killjoy, but I do not think this game is connected in any way to Go. Three points of putative correspondence exist: black and white stones, play on intersections, and a 19x19 board. I will discuss them in that order.
Hnefatafl pieces have actually been found. They are carved from bone (Bell, vol. 1, p. 80). Even if stones were used, however, it would be an understandable convenience for common people, or someone playing a game on the fly (e.g., soldiers in camp). Other games (e.g., mancala) also use stones. And if there are two sides, different colors are essential.
The intersections present a slightly more intriguing parallel. There are other games, including one tafl game, that use intersections: the Alquerque group, Fox and Geese (a tafl game), and Cows and Leopards (not a tafl game) to name a few. I have been unable to find any theory about the origin of intersections versus squares in games, but I offer my own speculation, which I think is plausible and even fairly obvious. I suggest that badly drawn lines are less disturbing aesthetically than badly drawn squares, and therefore are easier to make and preferable to use for the common people in ancient times. Aristocrats, on the other hand, could afford to have craftsmen make boards with neat squares. The antiquity of Go is consistent with this, and I suspect that it originated among the common people (contrary to legend). However, an even more practical explanation comes to mind for this game. A 19x19 board using substandard 1x1-inch squares would be very large, and with decent-size squares (say 1.5 inches to the side) it would be quite unwieldy. Therefore, it is far more practical to use intersections for games with large boards, as the lines can be more closely spaced. As an addendum to this, I should point out that the squares in Alea Evaneglii are subdivided with diagonals in some cases, and that many of the squares contain dots of unknown meaning (there are 10 dots in the castle squares, and six or seven in the attackers’ squares). Also, there are strokes in some squares. Therefore, the intersections may be used for the pieces because the squares are needed for these other elements.
The 19x19 board is obviously the most provocative parallel. Early Go supposedly used 17x17 (up to c. 700), but this sounds like it may be a detail about whether or not the frame was included. Similarly, at least one scholar thinks the frame in AE was not included (leaving 17x17) but the drawing seems to contradict this. The question is: why 19x19? My instinct suggests a symbolic significance. A cursory search in books on Chinese symbolism (most notably Williams’ classic Encyclopedia of Chinese Symbolism and Art Motives) yielded nothing. (Perhaps our Chinese members could add something to this?) Annemarie Schimmel’s great work, The Mystery of Numbers, notes that 19 is a sacred number in Egypt and among the Baha’is. But this is all pretty vague. More intriguing is that 19 years is the number of the Metonic cycle. Or perhaps it has something to do with the 361 points being one more than the degrees of a circle (recognized among the ancient Chinese as well as among other parts of the ancient world). It is a mystery, but if the answer lies in symbolism, then the symbol could very well be coincidentally common to far-flung cultures.