Definition: A 19th century invention that I just started trying to figure out.
My initial impression of sudoku was that that it was kind of like one of those 'word find' things since it first rose to my level of attention in the grocery store puzzle books. As my intellect and arrogance was clearly above all that I ignored it. For about 40 years.
Somehow I downloaded a Sudoku app a month or two ago and found out what the puzzles really were. Now it is my mental push up challenge every day. At least one 'Easy' one, a 'Moderate' one and a full crash into a 'Hard' one. I can usually finish the moderate level but have only completed one at the hard level and have never even looked at the New York Times puzzles.
I do them all with a British accent as a result of learning on this YouTube channel. They solve better with a British accent. Pro Tip.
The object for me is to never guess and never use a tip. If I can't suss it out I quit and sometimes come back to it or sometimes just move on and assume my skills will eventually increase.
One of my major concerns in life other than is loss of mental faculty. I see the deterioration over time and suspect it will never get better. As directed by Dylan Thomas, Sudoku is how I 'rage against the dying of the light' and is my love/hate go to method of maintaining some sanity. Only took me 40 years to find it.