Minimal givens must mean a good puzzle, right?

 Normal sudoku rules apply. The circled numbers are the sum of numbers along the attached arrows.
Any three consecutive cells in any one row contain exactly one of 1,2,3, one of 4,5,6 and one of 7,8,9. Any three consecutive cells in any one column contain exactly one of 1,4,7, one of 2,5,8 and one of 3,6,9.

 

0-8 Arrow

 Standard Arrow sudoku rules, but for numbers 0-8:

 Play online at: https://sudokupad.app/8ew2f5fqx5

Shifted Sudoku

Sudoku rules apply A clue indicates that number exists on a cell that shares a side with the clue.

Play online at https://sudokupad.app/dywunv9ufw

Harp

Enter a number from 1 to 9 in every cell. Numbers don't repeat in any row, column or outlined box. Numbers along the body of an arrow add up to the number in the circle. Numbers along a line ending in two circles are all larger than the number in one of two circles, and also all smaller than the number in the other. Click for web interface.

Commemorative

 This is a Thermo, X-Sums, Little killer sudoku.

On Oct 28, 1940 the Italian ultimatum was declined (" Όχι "), and Greece entered WWII. It is now a national holiday.

 

Descriptive Pairs Tile Sudoku

For once, the title is, well, descriptive. Every cell in the grid below contains a number between 1 to 9, inclusive. All numbers in the same row, or column, or bold outlined box are different. There are 16 rows, 16 columns and 9 boxes. Clues outside the grid take the form of a pair of numbers. For numbers i,j this means at least one of:

• the ith cell contains value j or
• the jth cell contains value i.

I discovered Tile Sudoku, and this particular layout, on Grandmaster Puzzles. I first spotted the descriptive pairs variation on Prasanna Seshadri's blog.

Desciptive Pairs Tile Sudoku

Hip hip...

Sudoku

Twenty one

When going to 11 isn't enough...

Every row, column and outlined region contains all numbers from 1 to 8, one per cell. All adjacent cells which differ by 5 are marked by a dot on their common border. Symbols outside the grid indicate a property shared by the first two cells in that direction. Same symbols mean same property, different symbols mean different property. Possible properties are:

• Big: number is 5,6,7 or 8.
• Small: number is 1,2,3 or 4
• Odd: number is 1,3,5 or 7
• Even: number is 2,4,6 or 8

Enjoy.

Way of the milk

Very easy; also, celebratory.

Shutter sudoku

Rules are painted on the picture. Lines extend across the central gap. Marks between triangles are not given. Hints regarding the placement of triangles are available if you mark the text after the bullets, which are after the page break. Apologies for the less-than-stellar image quality.

Killer Sandwich!

This puzzle was mostly created just so I could use the title. It's a typical killer sudoku, with a couple of sandwich clues thrown in. The sandwich clues give the sum of the numbers between the 2 and 4, (excl.) for that row or column.

Gratis free association links: Killer Sandwich

Are you scared yet?

I mean, I've been waiting for a decade and everything...

Greek Sudoku and Puzzle Championship writeup

This post ended up as a wall of text, so look under the fold at your own peril.

TL;DR version

I did much better at sudoku and much worse at puzzles than I anticipated. Puzzles were of modest difficulty but rather neat. Test format leaves a lot of room for improvement, including typesetting, problem type selection, and examination format. Still, fun overall.

Another easyish Sudoku

Sudoku are my go-to type for filling up long gaps in posting. There are a couple of points of low bandwidth, but I expect the overall shape will provide plenty of guidance on where to focus.

Symmetry + Symmetry = Asymmetry

This irregular sudoku is rather difficult. I would be interested in knowing how long it takes to solve. Also, the interactive environment this time is the scanraid solver, so I wonder how many will succumb to temptation.

Local fun

I participated in a local Sudoku tournament yesterday, and won myself some drink I'll have to pass to someone. Turns out there are pleasant, dedicated and organised puzzling folk nearby, which was news to me. Let me clue their name in an event-appropriate way:

2 grids, 4 minutes

Get your stopwatches out, read under the fold, and fill these two sudoku grids in four minutes or less.

Lent Sudoku

Or why fasts are not diets.

A complementary Sudoku problem

Inspired by the original T. Snyder’s “What If” article, I tried my hand at constructing a Sudoku problem whose difficulty increased as much as possible when a single element is removed, while retaining human solvability. This resulted in this pair of puzzles, one of which can be used as an introduction to Sudoku, while its near twin requires considerable experience to complete in a logical manner. Scanraid’s grader assigns them ratings of Gentle(27) and Tough (151), which concurs with my gut.
The puzzle below is the difficult one, while the easy version, and some spoilery commentary follows after the break.