199. This Riddle Can Be Numbers and Logic❓

RIDDLE 199:

I can be solved, and also confusing, a missing piece can create frustration, I’m a book and a type of mystery, played as a game, we all want the victory: What six-letter word am I?

Look for subtle clues in the title, background photo, and tags (tags are below).

ANSWER TO RIDDLE 199 IS HERE