Click a thumbnail to see its larger version and description.
The hardest of three versions, depicting numbers 1-16.
At least this version with numbers was marketed in Britain (as "it") too.
There was also a medium version (see the separate entry) and an easy version (very similar to Uriblock). All three came in at least two different designs. One named "Tsukuda's Square", the other "Four by Four".
There was also a variant "4x4" (no other title) with yellow frame and black pieces with white numbers.
For image 10 applies:
Courtesy, The Lilly Library, Indiana University, Bloomington, Indiana.
Thank you to the following people for their assistance in helping collect the information on this page: Geert Hellings.
This puzzle can be found in collections of these members:
Found a mistake or something missing? Edit it yourself
or contact the moderator