Tortoise Protocol is a large and hefty puzzle. Upon examining the internal structure, you'll see that it involves an incredibly intricate level of craftsmanship. In terms of the number of moves required to solve it-including even the small movements-it has the highest count among all the SD puzzles we have released so far.

The difficulty level of the puzzle is comparable to Dial Case, Mittan, and SDCB. While it includes some unconventional moves, careful observation and creative thinking about how each part might move should eventually lead you to the goal. In certain steps, there are multiple possible tools you can use-please consider which one is suitable and try to solve it in an elegant way. There is no need to strike the puzzle or apply excessive force. When environmental factors like humidity or friction affect how smoothly the pieces respond, you can still make progress by using gravity or gently shaking the puzzle.

The objective of the puzzle is to find the hidden compartment, and we've placed an item inside that clearly indicates when the puzzle has been solved. Initially, we considered names such as Turtle Recall and Akio Kame (with "kame" meaning tortoise or turtle in Japanese), but the former was ruled out due to the existence of a rock band with the same name, and the latter was avoided out of respect, as it might be presumptuous toward a great puzzle designer and maker.