I'm terribly sorry but I didn't understand what you meant to say...
Let's use your example. A row with a 1 5 1 in blue. Ok, what does this tell me? I know the numbers turn black if I tap in a certain place, does it mean I shouldn't have tapped there? What would you do in my place?
The reason I'm confused is because, from my way of reading its explanation, it seems the skill just tells you how many squares I should tap in that row but that's what the numbers do anyway! It's frustrating because the game seems to force that skill a lot and I can't use it xD
alright so, i'm bad with words so i'll try to break down what i mean and hopefully it makes sense that way
Let's go back to my 1 5 1 example
Let's pretend thats in a 15x15 and not 10x10, since it'd be harder to figure out.
How would you figure it out normally? Maybe count it out, use some other rows, things like that right?
In an empty 15 x 15, it'd be easy to look at it and realize you don't have enough to go on and maybe you'll come back later. But it's harder to see at a glance if there's more you can do there once you've messed with other parts of the puzzle.
Blue means that you can make at least one move in there without guess work. If it was blue but turned black, that means you either found the spot(s) or you accidentally entered the wrong spot (I usually do this when i forget to switch from fill to X)
e: To put it another way, if you activate blues you'll see at a glance what rows you can do SOMETHING in. Any black rows are a waste of time in that instance