From Dragon Ball Encyclopedia, the ''Dragon Ball'' wiki
Sugoroku Space (スゴロク 空間, Sugoroku Kūkan; FUNimation "Sugoroku Space") is an area in the universe.
When people were sucked into a wormhole, they ended up in Sugoroku Space. The caretakers would play a game to see if the individual had the desire to live. If the game was won by the individual, they could leave. If they lost, however, they would die.
Son Goku found himself stuck in Sugoroku Space with two Space Tanuki, Sugoro and Shusugoro, who had also been sucked in through a wormhole. In the process, their spaceship was somehow destroyed and they were stuck there for many years. When Goku arrived, they pretended to be the hosts. After Goku found out that the caretakers had been cheating all of those years, they tried to kill Goku by ripping the place apart. Goku saved Sugoro and Shusugoro and they all escaped.