Room of Spirit and Time
From Dragon Ball Encyclopedia, the ''Dragon Ball'' wiki
The Room of Spirit and Time (精神 と 時 の 部屋, Seishin to Toki no Heya; FUNimation "Hyperbolic Time Chamber") is a place located at Kami's Lookout. Inside the room, time seems to pass very slowly and there is a higher gravity level than Earth's. A step over the threshold of the training area brings one immediately into 10x Earth's gravity (the same as that of Planet Vegeta and King Kai's planet). The air gets denser and the temperature rises and falls the deeper one goes into the training area.
The Room of Spirit and Time has an entrance at its center, located in a central building with two side wings for housing, food supplies, bathing quarters, and sleeping quarters. Night or day does not exist within the Room of Spirit and Time, but the surroundings remain a constant bright iridescent white. Its reflective floor is of an undefined area and the room's boundaries are thought to stretch to infinity in all directions – though it appears to have a definite atmosphere, limiting its size. Son Goku explains to Son Gohan during their visit to the room that the air grows increasingly dense in the recesses beyond the plaza, which can be threatening as the Room of Spirit and Time has no definite boundaries. The Room of Spirit and Time represents an Alternate Dimension (異次元, Ijigen) from that of Earth.
The time dilation that occurs in the Room of Spirit and Time makes one day of real time equivalent to one year in the room, or one minute of real time approximately six hours in the room. There are dual giant hourglasses of emerald sand adorning the sides of the building that count down a year within the chamber. A clock on the dome roof of the main part of the building tells the applicable time in the real world.
This essentially allows for someone entering the Room of Spirit and Time to get one year worth of intense training in a single day.
The gravity in the Room of Spirit and Time living area is described as being "different", though it seems to not be much higher than Earth's gravity. The gravity of the training area is 10g. Gohan's first step over the threshold of the training area brought him to his knees (this does not happen in the manga, which explains how the gravity could feel "different" in the living area); Trunks also had some difficulty with the gravity, but Goku and Vegeta were both well accustomed to much higher levels of gravity by the time they used the room.
Those talking in the room have an echo in their voices akin to when a character thinks a word, rather than says it aloud. However, there are no solid objects other than the entrance for the sound waves to bounce off of.
The temperature in the training area fluctuates rapidly, ranging between -40F and 122F, and the air pressure is a quarter of Earth's (in the anime, the air is said to grow denser the deeper one goes into the chamber). Goku, Gohan, Vegeta, and Future Trunks are the only characters shown to go deep into the room. It is not shown if Piccolo, Son Goten, or Trunks did, though it seems unlikely that any of the three would have had much trouble with it.
The wooden door entrance is a portal between Earth and the Room of Spirit and Time, and it is the only way to travel between the two dimensions without ripping holes in the dimensional walls.
The room can only be entered for two days (or two years) at a time. If anyone attempts to stay longer then they will not be able to exit, leaving them in nothingness and not allowing anyone else to use the door. Also, there are only enough provisions to accommodate two people for a full year. This is commonly misinterpreted as a two-person limit overall, but it should be noted that in the Boo Saga four people in total entered through the main door. Vegeta and Trunks are the only two to enter the room for two entire days, though due to their lack of mastery of the Super Saiyan form they increased far less than Goku and Gohan had in less than one year inside. Goten and Trunks are the last to train in the room when, upon Boo's transformation into Super Boo, Piccolo decides to give them time inside. In less than half of the hour (roughly one week inside the chamber) that Piccolo told Boo to wait, they achieve all three Super Saiyan levels.
 Approximate time dilation
Time passes 365.25 times faster in the Room of Spirit and Time than in the real world, making one day outside the chamber equal to 365.25 days within it (one solar year).
|Real world||Room of Spirit and Time||Calculation|
|1 Day||365.25 Days (1 year)|
|1 Hour||15 Days, 5 hours and 15 mins|
|1 Minute||6 hours and 5 minutes|
|1 Second||6 minutes|
 Dragon Ball Z
 Imperfect Cell Saga
Main article: Imperfect Cell Saga
Vegeta and his son Future Trunks enter the room to train for their attempt to prevent Cell from attaining his complete form. Both train as ascended Super Saiyans, and Trunks surpasses his father in brute strength, but has issues with not getting in the way of his father's pride, so Trunks hides his power level. Trunks unknowingly makes a mistake by using his time in the Room of Spirit and Time to increase his strength, while sacrificing his speed and dexterity. Both Vegeta and Trunks fail to prevent Cell's completion, although Vegeta deliberately took part in allowing Cell to become complete for the sport of fighting him at a more challenging state.
 Perfect Cell Saga
Main article: Perfect Cell Saga
Goku and his son Gohan enter the room in preparation to fight against Cell. While training with his father, Gohan becomes a Super Saiyan, becoming the youngest Super Saiyan of his time. They both emerge from the room with a heightened control over their Super Saiyan transformation. They developed an optimisation technique to stay in the Super Saiyan state for long periods of time in order to eliminate the strain from transforming. This allowed them to save energy for fighting, and worked so well they could even sleep while in Super Saiyan form. This training greatly assisted in Gohan's upgrade to Super Saiyan 2 during the Cell Games.
Piccolo entered the room for meditation and self training, followed by Vegeta and Trunks entering again, increasing their power levels even further (although not quite surpassing Goku and Gohan). Piccolo reached a level of power equal to or possibly greater than Cell in his semi-perfect form (given he could hold his own against a Cell Jr., a much more powerful foe than "semi-perfect" Cell). Trunks and Vegeta's power levels didn't increase near as much as the first time they entered (possibly due to the fact that unlike last time, they acquired no new forms during this period, instead focusing on powering up their regular Super Saiyan state to its maximum), but they still improved enough to put up an evenly matched battle against the Cell Juniors. The Room of Spirit and Time was not used again until after the Cell Games.
Goku tells Gohan that he was here when he was little, even though we have never seen it, it is possible he did go into the chamber when he was training there during the Piccolo Jr. Saga.
 Fusion Saga
Main article: Fusion Saga
Goten, Trunks, and Piccolo enter the Room of Spirit and Time to lure in the horrible Super Buu. When Buu enters the Room of Spirit and Time, Trunks and Goten use the Fusion Dance technique to become Gotenks. They introduce their Super Ghost Kamikaze Attack and upgrade themselves to Super Saiyan while fused. During the battle Gotenks falsely says he can't win in hopes of creating a more dramatic victory. Believing the act, Piccolo destroys the Room of Spirit and Time's entrance, leaving no way out. Buu can't stand the thought of being stuck in the Room (mostly because of his fondness towards chocolate, and the lack of it in this dimension). So Buu in an intense rage, screams at the top of his lungs. The scream is so loud, that it rips a hole leading back to Earth's dimension. Buu gets out but it's too late for Gotenks and Piccolo, as the portal closes behind him. Gotenks and Piccolo attempt to recreate Buu's mad howl, and succeed only after Gotenks transforms into Super Saiyan 3, and yells their way out.
The Hyperbolic Time Chamber is rendered non-functional without a door and must be repaired for future use. It can be argued that when Buu destroyed the Lookout in later episodes, the Room of Spirit and Time could have been fully repaired because the Lookout was wished back damage free, whereas in the video game Shin Budokai it is mentioned that Piccolo fixed the door after the lookout was wished back.
 Video games
The Hyperbolic Time Chamber is featured as a playable battle stage in the game Dragon Ball Z: Budokai Tenkaichi and both of its sequels where, for the sake of playability, a transparent wall encloses the plaza (rather than the area surrounding it being infinite as it is in Dragon Ball Z). It is also featured in the crossover fighting game Battle Stadium D.O.N as a playable battle stage
The Hyperbolic Time Chamber, or rather its entrance/exit, also make a cameo in the barren planet stage of Dragon Ball Z: Burst Limit. In Dragon Ball Z: Sagas, it is used to train Gohan, Trunks, and Vegeta to transform into Super Saiyans. The Hyperbolic Time Chamber also appears in Dragon Ball Z: Buu's Fury when training as Goten and Trunks. The Hyperbolic Time Chamber also appears in Dragon Ball Z: Supersonic Warriors 2 where it is named the Time Chamber.
While the outskirts of the chamber are clear in the anime, most of the video games show them as having a blueish kind of color.