Notes to V2V (VI)

V: Even Sandwich
I like to explore the possibilities that certain types offer. In the case of Even Sandwich there are some interesting steps during the solve that make it a lot easier to proceed, one of them very early in the process. Also: by knowing there is an even digit and no sandwiched digit in the respective row or column there must be odd digits two cells away from the even digit.
R5C3 = 2; 9 in row 4 in R4C45; R4C6 = 2; R4C4 = 9; R4C57 = {46}
R35C4 = {48}
3 in C5 in R23C5; R3C6 = 1; R1C4 = 5; 5 in C6 in R56C6; R6C5 = 7; R6C4 = 3
R1C36 = {68}; R1C2 = 9; 9 in R9 only in R9C3 :=> R9C4 = 2; R9C2 = 8; R9C6 = 7
R9C78 = {16}
1 in R8 in R8C3; R8C2 = 2; 7 in Block 7 in R8C1
R5C1 = 3; R46C1 = {19}
…

V2V: Sum Sandwich
Thinking about a variation to Even Sandwich, more ideas crossed my mind. I used two of those ideas for the Advent Calender at Logic Masters Germany, namely Consecutive Sandwich and Next to Nine. I thought the third idea would be suitable for this test: Sum Sandwich. I realised quite a lot of puzzles for the test were already on the hard side, so I decided to make this one very easy. The sums of 3 and 4 provide easy starts for this puzzle.

Notes to V2V (VII)

Here are the final notes to the test puzzles.
Please feel free to respond, ask more clarifications, point me to other solving strategies (or typo's).

1~9
Playing with sums in sudokus is one of my favourite habits. I really liked the idea of a ‘floating sum’ somewhere in the row/column immediately when I saw it once at a Sudoku Cup. Deriving information from the grid, limiting the positions of 1 and 9, it’s all in here.
R2C3 = 4; R2C4 = 9
In row 8 the digit outside the sum is 2 (33 +1+9=43), so: R8C1 = 2; R8C2 = 9; R8C9 = 9
Column 2: digits in R19C2 must be {68}
Column 4: since R8C4 <>1; R9C4 = 1; R1C4 = 6
Column 3: digits outside the sum add to 8; 1 or 2 cells. Since R89C3 <>1 and 9: R1C3 = 9; R7C3 = 1; R89C3 = {35}
…

Frame 1~9
I had little reservations towards this type. I am not too fond of sudokus with complicated rules and I was a bit afraid that the large number of clues outside the grid would be confusing.
I liked the fact that on one side you give more information about each row and column, but on the other side, by giving the clues in an increasing order, you take away information as well. So all in all, I gave it a go.
Important information: no zero outside the grid means no 1 or 9 in the first and last cell, and no neighbouring 1 and 9 as well.
Wheather people found all those outside clues confusing during solving or not I can’t tell, but it’s the puzzle with the highest percentage of correct entries.
R28C5 = {19}
R6C9 = 2; R5C9 = 1; R7C9 = 9; R9C8 = 1; R9C9 = 7; R8C9 = 3; R78C8 = {25}
R9C7 = 4; R8C7 = 6; R8C8 = 5; R7C8 = 2; R9C1 = 9
9 in R4 must go in R4C4; R4C13 = {78}
…

Hi Richard, thanks for the contest, nice Sudokus as expected. My performance felt like average for me, and had no luck too with the timing, missed the Sum Sandwich by maybe 30 seconds (but thats only 30 points). I felt I needed a break after the last contest, so I had some more or less puzzle-free weeks and no preparation, otherwise I think I would have felt "overpuzzled" in the upcoming WPF Grand Prix' and of course the German Championships. Now it's time to start training again ;-)

After solving the remaining half, I'm happy I didn't do the Greater than X. Nice path and my favourite in the set, but would have cost much too much time in the contest.

How balanced do you think the puzzle types of this test were?	Perfectly balanced
What was your opinion of the distribution of easy/hard puzzles?	Just right
What did you think about the puzzle quality of the test?	Fairly Nice
How did you feel about the length / time limit for this test?	Just right
Of the puzzles you solved/attempted, how well did their point values reflect the difficulty/time spent?	Most puzzles were worth the right amount
What was your opinion of the booklet formatting and printing?	Just right

Enjoyed the test, albeit I had to do it in something of a rush. Thanks Richard!

How balanced do you think the puzzle types of this test were?	Perfectly balanced
What was your opinion of the distribution of easy/hard puzzles?	Just right
What did you think about the puzzle quality of the test?	Very nice
How did you feel about the length / time limit for this test?	Way too many puzzles (too little time)
Of the puzzles you solved/attempted, how well did their point values reflect the difficulty/time spent?	Most puzzles were worth the right amount
What was your opinion of the booklet formatting and printing?	Just right

When I say "too little time" means I need much more to solve all puzzles. However, the contests shouldn't be any longer (I even would prefer shorter, but I understand that it is than more difficult to have a balanced choice of puzzles). So the time is really ok.

How balanced do you think the puzzle types of this test were?	Fairly balanced
What was your opinion of the distribution of easy/hard puzzles?	Just right
What did you think about the puzzle quality of the test?	Very nice
How did you feel about the length / time limit for this test?	Just right
Of the puzzles you solved/attempted, how well did their point values reflect the difficulty/time spent?	Most puzzles were worth the right amount
What was your opinion of the booklet formatting and printing?	Just right

How balanced do you think the puzzle types of this test were?	Fairly balanced
What was your opinion of the distribution of easy/hard puzzles?	A bit hard
What did you think about the puzzle quality of the test?	Very nice
How did you feel about the length / time limit for this test?	Way too many puzzles (too little time)
Of the puzzles you solved/attempted, how well did their point values reflect the difficulty/time spent?	Most puzzles were worth the right amount
What was your opinion of the booklet formatting and printing?	Just right