We see Hnefetafl being played in the past two chapters (104 and 105). Apparently this turned based board game of strategy was very popular in Scandinavia during the viking times. Later variants would develop in other regions.

http://en.wikipedia.org/wiki/Tafl_games

Opinions on the game? What do you believe it symbolizes in Vinland saga?

For me chapter 104 symbolizes...

Halfdan feeling he can have full control over everything, and how everyone will act as he wants/expects.

Chapter 105

Sigurd's lack of awareness, recklessness, and not taking ruling seriously.