JCO Website (Puzzles for the manual solver)

Welcome!

This is a place chosen to make available some ideas (on puzzles, patterns, etc)

that seemed unsuitable for posting in a Forum, but some people may find interesting.

For difficult puzzles, possible solutions will not be shown (only hints).

For other puzzles, the solution wil be hidden so that a serious attempt can be made

without direct access to a solution.

(hopefully this will make the puzzles more interesting for newcomers)

(Guidelines for using this site here)

Links for Basic Concepts

(useful to look up for the meaning of some unfamiliar concept)

Rules

Recent Puzzles (*1*)

Puzzle HP#15 (overall #137) (7x7 Hidoku Puzzle; proposed September 12, 2026)

I propose this newly created Hidoku puzzle (for a manual solution !)

Hidoku Puzzle

Hint (Update 1: hints for the key move 1)
  .---------------------------.
7 | __  __  __  01  __  __  __|
6 | __  19  __  __  __  42  __|
5 | __  __  __  31  __  __  __|
4 | __  22  __  30  __  __  __|
3 | __  __  __  __  35  __  12|
2 | __  __  __  __  __  __  __|
1 | __  __  __  49  08  __  __|
  '---------------------------'
    a   b   c   d   e   f   g
    
Update 1 (Sept 13, 2026)

This puzzle has a very tough beginning, but after working
hard in the first move, placing a key number, only easy
deductions are needed afterwards ! 

Some hints for the key move 1:

. study important connections, like 01-08, 12-19, etc, and the
  possible paths for each connection.
. special attention to unique passages is very important, like
  f3, d3-f4, c4, and a few others.
. In summary: global view is better here than local considerations.
    

Recent Problems (*0*)

Past Puzzles (*136*)

Past Problems (*6*)

Interesting Forums ( in particular, very fond of the NSPF! )


Created: February 12, 2024

Contact: sudo.jco.br@gmail.com