It was created to allow one to travel to any destination be it far for near.
As it revealed in Four's a Crowd Washu convert the portal to appear on the inside of Tenchi's blanket as she and the others can enter his bedroom anytime they want, However a flaw of the portal is revealed in Long Distance Lunacy that if the Blanket is folded in a certain way, it would close the tunnel, preventing the girls from popping in whenever they want to come and the only way to open the portal is for Tench to fold the blanket out, allowing the tunnel to open.
It was first used by Washu as she finished testing it as she exist out of it and scared Ayeka. It was then used again when the girl rescue Tenchi and his grandfather from a group of Ghost that represent greed.
When Tenchi woke up on his first day alone in tokyo, he sees Ryoko next to him in bed and discovered that Washu has tested the portal and connected it inside Tenchi's bed so now they can come see him anytime they want, Later while at the Masaki's house Washu told the girls she completed the portal and both Ayeka and Ryoko attempt to have the portal intsall in their own rooms but as they each pulled the portal, it bounced around the house until is landed on the ceiling, so now the portal is stuck up there, which Ryoko use her fliying powers to enter the portal and Ayeka using a ladder to climb up there.
Before heading to school, Tenchi discover away to close the tunnel from his house to his apartment; if he fold the blanket in a certain way, the tunnel is closed, preventing the girls from popping in whenever they want. Ryoko attempt to enter the portal by herself, only to learn that it's close and with all her might, manage to opened and made it into tokyo. However Tenchi sent her right back inside the portal and told her the tunnel is close until further notice.
However near the end of the episode Tenchi reopened the portal and told the girls he got them cookies, with Ayeka using the ladder to climb up and drag Tenchi down, returning him home.
Like before Tenchi folded the blanket,closing the tunnel as Sakuya wanted to take Tenchi Sight-seeing through Tokyo. During the first half of the episode Ryoko and Ayeka attempt to enter, only to learn that Tunnel is close but with only a small entrance. Washu explain that only Tenchi can open the portal from his side, Which Ryoko attempt to open it by an energy blast, which no effect. Then Ryoko and Ayeka plan to use Ryo-Ohki to enter the tunnel and folded the blanket. As it seem all hope is lose Ayeka use a spork and stab Ryo-Ohki in the butt, resulting in her entering the tunnel and fold the blanket.
Though unseen, Sasumi used the portal to travel to japan and brough Ryo-Ohki with her as she use he to preform tricks with a ball as Sasami raised enough money to buy a new broom.
Sasumi used the portal to staywith tenchi for a while when she told him how the other girls wanted the money she collected from the last episode
- Ryoko = Needed Change.
- Mihoshi & Kiyone = Needed to borrow the money to buy back the Galaxy Police identification and hand cuffs they pawned last week before they were sold.
- Washu = Needed the money for a new invention
- Ayeka = Needed it to by beauty products.
The Portal has malfunction, forcing Tenchi to buy a ticket back home for the 2 year anniversary of how he and the girls met.
The Guardians of Old
Having seeing a news report at a archaeological dig, where Tenchi and his classmates are at for a school field trip, Ryoko attempts to use the portal to see Tenchi, only for Ayeka have Azaka slam Ryoko into the ceiling, while Kamidake floated her up there. But as Ryoko attempts to enter the portal, Ayeka folded the blanket just in time, closing the tunnel and off to the dig sight, meanwhile Ryoko stomping on the portal, demanding Ayeka to open it and calling her a coward.