Timeline

This is a fan-made timeline and is not official. Different translations may differ on the amount of years and exact dates are rarely given.

Early on, it was mostly assumed the events of the beginning of the series occurred when the first OVA was released, August 1992, and successive dates are determined by ages given to characters Sasami is called 9 years old when it should be "1993" (her time in stasis is not counted). Comments about time passage, like a title card that says "5 years later" or "It's been 10 years sing Kiyone passed," are used to add and subtract years. A calendar in OVA 4 shows a month matching September 1994 (or 2005, 2011). Still, not everyone agrees and anachronistic details confused the assumed timelin (like a flip cell phone in 1993- three years before the first was available, or a 2003 model vehicle being depicted 10 years before it's "supposed" to be).

However, by the time that the fifth season of Tenchi Muyo! Ryo-Ohki and Tenchi Muyo! GXP Paradise Starting were being released, it was becoming evident that the timeline had started using a "sliding timeline," in which the time being being depicted was accurate to the contemporary period the shows were being released, and could no longer be considered to be following a timeline that definitely started in 1992. So, starting with the "Present Timeline" (and a little before) the timeline instead works with a "Year Zero" in which things are noted as occurring relative to the year in which the events of the episode Ryoko Resurrected.

This is no longer quite the timeline it is based on and referenced, it is a group-sourced improvement adding details that have since been clarified and events that had not occurred when it was first made..

"When we came to this world, both Tsunami and I began to consider enjoying our methods of achieving our goal." -Washu

"Although we created it, this world is delightfully fascinating. It would be a terrible shame to rush right through it!" -Tsunami

Pre-Tenchi Muyo

Early Galactic History

Translations for the age of The Great Prehistoric Civilization have differed, usually 1 Billion or 100-million years ago.

A sentence in the official translation of True Tenchi Muyo! Volume 1: Jurai has Azusa refer to the civilization that seeded the Earth as existing "billions" of years ago.

Suffice to say, it was "a long time ago."

It seems that, although seemingly illogical, the correct translation is "one billion years".

Timeline	Events Occurred
Pre-History	Three nigh-omnipotent, omniscient, pan-dimensional beings come into creation, Washu, Tsunami, and Tokimi: The Chousin. They have inexhaustible power but realize there is a possibility of one even more powerful than themselves. Faced with this possibility, they create the multi-verse as a way to experiment in ways to also bring this being to creation.
Early Galactic History 1	Washu and Tsunami descend into the 3rd dimension, believing it the best way to look for this higher being. Washu creates her gems to power creations to aid her efforts. Tsunami's early efforts include giving first generation tree seeds to early civilizations. Tokimi stays in the upper dimensions to continue her efforts working from the outside.
Early Galactic History 2 (Dual time minus aprox. 100 thousand years)	About 100,000 years before Great Prehistoric Civilization. Washu is captured by a precursor civilization. Three clone-bioroids of her are created, each given one of Washu's gems and divided between galactic powers. The third (B3) escapes its ruling nation and B1 and B2 are sent from their nations to kill her, this results in a devastating intergalactic war that hastened this early civilization's downfall. B3 is barely able to kill B2 and B1 kills B3. B1 takes all the gems and attempts to kill the imprisoned Washu. Tsunami awakes to kill B1 and return the gems to Washu, still in confinement.
Early Galactic History 3 (Dual time minus aprox. 1-10 thousand years)	A spaceship flees their war-torn world and, while the crew is in cryosleep, crashes on a primitive "Earth" with an intelligent human race. In order to make themselves seem superior to the primitive residents, they transform their ships into humanoid robots that can be seen as objects of worship. The two most powerful are ZINV and HIMC which each are powered by seeds received from Tsunami. This group separated into a camp that wanted to stay settled on the planet and another that wanted to return to space, they fought and destroyed themselves. The only survivor was D, a girl whose body had almost been destroyed but her astral preserved in a bioroid. She gathered the remnants of their technology, sealed it off, and went into stasis within.
Early Galactic History 4 (Dual time)	The core events of Dual Parallel Trouble Adventures occur. Kazuki Yotsuga travels into space with Zinv and ultimately he and the others become the progenitors of what becomes the "Great Prehistoric Civilization." At some point, D's astral is copied or preserved in an AI and is left to sleep again with Zinv underground.

Parallel Universe History

The events of Photon: The Idiot Adventures occur in an unknown time frame, 10,000 years before the world first becomes known as Geminar. It is theorized (only a theory) that events of the series separated the dimensions into those of Tenchi's universe and the Geminar universe (the second "Earth" created would probably have been the Earth of Dual) so that would place it very early. But time moves oddly on that side (Sometimes time is synchronous but during certain periods, thousands of years pass in Geminar while only a couple decades pass in Tenchi's dimension) so it's impossible to gauge when in this chronology it occurred. However, it has been noted in the OVA and doujinshi, that Tokimi has had a particular interest in Geminar ("Geminar is one of Tokimi's worlds") and in fact, the main gate in the Holy Land was built in her likeness. In a 2017 doujinshi, Tokimi's essence is linked to the concept of "time"... so it could be likely that she has played around with time there.

Galactic Federation Timeline

The Great Prehistoric Civilization proves to be extremely resilient, spanning much of the galaxy and lasting for hundreds of millions of years before splintering.

Although not the first or last, this civilization starts the greatest "seeding" project in galactic history, spreading the human genome to proto-planets at the beginnings of life even outside their own territory. And, somehow, were also able to seed recurring cultural norms that resulted in future worlds, languages, tools, foods, etc. replicating their own. In the case of Tenchi's Earth, a virtual copy of that of Dual's Earth and the entire solar system.

After The Great Civilization broke up and before The Galactic Federation, there were tens of thousands of smaller Galactic nations. As space is so vast, war was mostly pointless and these nations mostly focused on exploring the unexplored areas. It was known as The Age of Galactic Exploration.

However, it seems both Tsunami and Washu remain dormant over this time, never sensing a need to interfere. In the lives of infinite beings, a billion years may seem a short period of time.

Timeline	Events Occurred
150,000 years ago	A member of a wandering pirate guild encounters the giant, sleeping form of Tsunami on a forest planet. Detecting traces of potential in his offspring, she made a pact with this man to protect him and his descendants. As her giant body had already begun to turn into a tree, she completed the process and her physical form became the giant tree Tenju. Jurai Empire is founded. Earth is discovered and secretly registered by the Emperor's sister, Masaki. Masaki settles on Earth and eventually copies and preserves her astral and hides it on the moon.
150,000-100,000 years ago	Apart from Jurai, Seniwa also spread its influence, eventually dominated by the Kuramitsu family. Although both possess superior Technology, neither alone is large enough to form a true galactic alliance and end up in a seemingly endless cold war.
28,000 BCE	Five ancient mecha were found on an abandoned planet, Terra, along with other robot technology. These five mecha each had 3rd Generation Royal Tree Seeds in them, like Zinv's 1st generation seed. The five were divided between the "Five Legendary Heroes" and these five heroes formed the kingdoms of the Renza Federation. However, they are cut off from the rest of the galaxy by distance and pirate activity.
18,006 BCE	Naja Akara is born.
18,000 BCE	The core events of True Tenchi Muyo! Volume 3: Washu begin. The facility that held Washu-sama prisoner for millennia ceases to do so (rumored partially due to age and partially due to Tsunami). Washu later appears on planet Kanamitsu as an infant with no memories of her past, but with three mysterious gems.
17,983 BCE	First negotiations between Jurai and Seniwa
17,982 BCE	Miyuki and Mikumo were born.
17,000 BCE (aprox)	Jurai and Seniwa form an alliance, smaller nations start to join what becomes The Galactic Federation. Mikumo's private army forms the core of the Galaxy Police, The Juraian Imperial Academy becomes the Galaxy Academy.
8000 BCE	A planet in a solar system bordering multiple nations is discovered with evidence of early civilization and is thought of a possible location of the home planet of The Great Prehistoric (The Earth or Mars of Dual) and designated a site of historical importance. But the researcher working on the discovery dies, his research lost, and the bordering nations agree to mark it off limits to anyone. A group from the Wau race migrate there. Unknown to all, Zinv sleeps below its surface.
3000 BCE	Naja disappears on K1190 during a pirate attack while at the same time, a young girl with amnesia appears on K1190 and is rescued by a member of House Kamiki from Jurai, becomes Seto Kamiki Jurai. Washu, in her grief, attempts to clone Naja, but by using one of the Ryoko prototypes it becomes something new and she calls it Kagato and makes it her assistant. Kagato was originally a hermaphrodite but the male half separated the female part of himself into a child. Kagato imprisons Washu and little Ryoko and Ryo-Ohki. He takes Washu's ship, Soja, and embarks on a mission to steal galactic artifacts that can bring him power. He also attempts to kill the young female Kagato. This female Kagato is pulled from her time when a time and space displaced Tenchi saves her.
1200	A GP officer named Kazuki is assigned to Jurai. There, he meets the Juraian Princess from house Masaki, Amame
1239	Azusa is born to Amame, having given up her royal title to be with Kazuki.
1246	Funaho is born
1247	Seto travels to meet Azusa
1249	Azusa's original home planet is attacked by Pirates. Seto finally convinces Azusa to come to Jurai to head the practically abandoned house of Masaki.
1252	Mitsuki Amaki dies, freeing her 1st generation tree to become Azusa's, he names it Kirito.
1256	Misaki is born.
1259	Space Pirates arrive on Earth, their arrival triggers Masaki's registration and makes it Jurai's territory.
1260	The core events of True Tenchi Muyo! Volume 1: Jurai begin. Azusa and Kagato dual. Azusa is defeated in personal battle and after he retreats to Kirito, the fight with Ryo-Ohki and Ryoko created a dimensional rift. To seal the rift, Tsunami appears and transports Soja and Kirito from the spot. She Transports Kirito to Earth. In the process of defeating the pirates on Earth Azusa meets and falls in love with Funaho, Azusa also finds and talks to the projected astral of Masaki. Azusa is summoned to Jurai because the current emperor is dying and takes Funaho with him. The emperor dies and Azusa is crowned.
1266	Azusa marries Funaho
1267	Airi Magma is born
1270	Yosho is born.
1275	Azusa marries Misaki
1278	Yosho is chosen by and bonded to Funaho-tree, Ayeka is born.
1280	The core events of True Tenchi Muyo! Volume 2: Yosho begin Yosho enrolls in the Galaxy Science Academy, meets Airi and Kanemitsu Hirata.
1282-	Misaki and Funaho create a marriage pact for Ayeka and Yosho.
1284	Minaho is born.
1289-	Sasami is born.
1292	Ryoko attacks Jurai. Ayeka is bonded with Ryu-oh. Third Generation Juraian Treeships "hesitate" before attacking Ryo-ohki. Tsunami assimilates Sasami. Yosho chases Ryoko to Earth and defeats Ryo-oki. Ryoko takes Kasumi (Funaho's niece) hostage. Yosho defeats Ryoko and takes her final gem. Yosho survives a final desperate attack by Ryoko, but does not kill her as she reminds him of Ayeka. Yosho seals Ryoko in a cave and marries Kasumi.
1297	Ayeka leaves in search of Yosho. Sasami goes with her.
1350 (aprox.)	The events of Spaceship Agga Rutter presumably occur around this time. The beginning of the decline of The Shank Pirate Guild.
1414(aprox.)	Yosho contacts Kanemitsu. His location on Earth immediately becomes known to Seto because of it. Yosho learns he is the father of Minaho.
1760 (aprox.)	Kiyone Masaki born
18xx	Nobuyuki Masaki is born
Year -79	Tennyo Masaki born to Kiyone and Nobuyuki
Year -23	Mihoshi is born (estimation- needs a source)
Year -16	Tenchi Masaki is born
Year -15	Kiyone discovers Rea, aged approximately 12 years, in a field, having just been sent from Geminar. Kiyone brings her home and she joins their family.
Year -14	Seina Yamada is born
Year -8	Kiyone Masaki dies

"That was 20,000 years ago that I had a husband. I am still very young. And I'm lonely, come bedtime... Ah! I'm so embarrassed! -Washu

Present Timeline

The core events of Tenchi Muyo! Ryo-Ohki begin. As mentioned in the introduction, the timeline originally seemed to start in 1992, but eventually it becomes apparent that the time depicted no longer matches a timeline that starts in 1992. Events that should be occuring around the year 2000, were clearly being depicted as happening at least ten years later.

Timeline	Events Occurred
August Year 0 (originally considered August 1992)	Tenchi Masaki accidentally frees Ryoko Hakubi
September Year 0	Ryoko is officially resurrected. Ryu-Oh enters Earth's orbit. Ryo-ohki-san is destroyed. Ryu-oh is damaged so badly it can not fly by itself as a ship. Tenchi's house is relocated near the Masaki shrine. Ryoko, Ayeka and Sasami become the official residents of the Masaki house.
October Year 0	Ryo-Ohki-chan is born. Ayeka discovers Funaho-tree and realizes that Yosho is still alive.
December Year 0	Mihoshi crash-lands on Earth. Her shuttle falls into subspace. Kagato makes a comeback.
January Year 1	Ryoko creates the Floating Onsen.
February Year 1	Kagato comes to Earth seeking the ultimate power and kidnaps Ryoko. Katsuhito is revealed to be Yosho. Yosho gives Funaho-tree to Tenchi. Ryo-ohki-chan and the remains of Ryu-oh fuse into Ryu-ohki. Ryu-oh is destroyed with Tenchi. Tsunami appears and resurrects him. Mihoshi releases Washu. Tenchi creates Light Hawk wings for the first time. Kagato is destroyed, and so is Soja.
March Year 1	Ryu-oh is resurrected. Mihoshi's shuttle is pulled out of subspace. She returns and submits her report. Masaki house is destroyed by Mihoshi's shuttle.
April Year 1	Nobuyuki rebuilds the Masaki house. The truth about the Sasami/Tsunami relationship is discovered. Ryo-ohki-chan fuses with Masu. Dr. Clay is assigned by Tokimi-sama to capture Washu. Zero replaces Ryoko. Washu and Dr. Clay duke it out after so many years. Dr. Clay explodes the lower portion of his ship. Tenchi uses Light Hawk Wings for the second time. Dr. Clay is captured and escorted to Galaxy Police. D3 erases Dr. Clay's memories of his dealings with the Choushin. Z destroys a fleet of ships sent to attack Tokimi's "temple." Tokimi-sama issues a warning to Z to not touch Tenchi.
May Year 1	A Jurai delegation arrives on Earth. The truth about Yosho is revealed. Funaho asks Washu not to make another Ryo-ohki. Washu assures her that it will never happen. Tenchi fights Seriyo and wins (thanks to Mihoshi.)
Spring Year 1	Mihoshi sends a letter to her twin brother Misao. The letter is intercepted and modified by Z. Tennyo, Tenchi's older sister, arrives to reveal herself to Tenchi and to announce his arranged marriage to Noike Kamiki. Noike arrives and moves into the Tenchi household on Earth. Tenchi meets his grandmother Airi-san and sees the true face of his grandfather Yosho, where he is then let in on the Masaki family secret.
June Year 1	Misao arrives in the giant spherical battleship Chobimaru to rescue Mihoshi from what he thinks is the evil Tenchi. Mashisu's elite special forces unit are defeated by Ayeka, Ryoko, and Sasami-chan. Ryo-ohki and Ryoko defeat the Chobimaru. Z destroys a large chunk of the Earth to draw out Tenchi and to make him use his LHW's for the third time. Z brings out the counteractor, who is revealed to be Misaki. The counteractor nearly kills Tokimi-sama. Tenchi is sliced by Z and sent out of the timeline to the past, then to the future before returning to the present where his kami-self is revealed, which kills Z. Tenchi-kami-sama calms Misaki and takes her away leaving the Choushin to fix the damaged universe and to reset time back so that the events Z caused won't happen. Z is returned to the timestream as a normal person to live a normal life.
Spring Year 1	Mihoshi sends a letter to her twin brother Misao. The letter is intercepted and modified by Noike from the future. Tennyo, Tenchi's older sister, arrives to reveal herself to Tenchi and to announce his arranged marriage to Noike Kamiki. Noike arrives and moves into the Tenchi household on Earth.
June Year 1	Misao arrives in the giant spherical battleship Chobimaru to rescue Mihoshi from what he thinks is the evil Tenchi. Mashisu's elite special forces unit is defeated by Ayeka, Ryoko, and Sasami-chan. Ryo-ohki and Ryoko defeat the Chobimaru. Noike causes the Chobimaru to fire its main weapon at Earth, causing Tenchi to use his LHW's for the 4th time, this time manifesting six wings instead of three. Misao and his grandfather (the head of Galaxy Police) are punished for their role in the attack on Tenchi and Earth. Mashisu is adopted into House Kamiki, thus giving Seto-sama control over the Chobimaru (though it is still part of the Galaxy Police force).
July Year 2	The core events of Tenchi Muyo! GXP begin. Amane arrives and delivers the GXP pamphlet to Seina. Within a week, Seina goes into space, accidentally attracts his first gigantic group of pirates. meets Seto (who gives him special permission despite being a human from an undeveloped world), meets Ryoko Balta and Erma (obviously not at the same time), enrolls in the Galaxy Police Academy, (unknowingly) captures the serial killer Widow (he inspires her to turn herself in), crashes the entire computer system of the academy, and (again, unknowingly) makes Kirche fall in love with him. All before his first class.
Fall Year 2	Rea reveals how she is from a world in another dimension named Geminar, she thought people already knew. Nobuyuki marries Rea. Tokimi and Washu remove Dr. Clay's seal from the astral of female Kagato/Noike. Miki Steinbeck is apparently killed by Tarant Shank, actually her AI is freed and she starts sabotaging his plans from his ship's computers and his home base. Seina soon attracts Kyo Komachi and Tarant Shank, despite not being anywhere near where Pirates should be. Soon after he is assigned to be captain of the Kamidake. Seiryo Tennan is captured by Kyo.
Winter/Spring Year 3	The first Kamidake is decommissioned after taking too much damage. Seina meets Neju Na Malmus, Fuku is delivered to Seina and he runs his first mission with the Kamidke II. Tarant Shank tries to attack Earth, maybe to kidnap Seina's family, Tenchi and crew easily defeat him in a humiliating fashion.
Summer Year 3	Tarant Shank tries to capture Seina and the Kamidake, they fail and his first seemingly indestructible Daedalus is destroyed. Seina visits Tenchi on Earth for the first time after going into space. The pirate's first Good Luck Fleet wrecks havoc with the galaxy but is defeated quickly by Seina after being called back from his vacation.
Fall Year 3	Rea gives birth to Kenshi Masaki, Tenchi's half-brother. Tarant, after many humiliations, is forced to give up the schematics of the Daedalus to get back in the good graces of the Daluma Guild again. They begin building what will become the Unko, based off the designs. The Tennan corporation goes into business with the Daluma pirates to make and gather good luck items, Seiryo is ordered to aid them.
Winter Year 4	Kiriko is adopted into the Royal Masaki House (directly- it is not known she is a descendant of Yosho) and is paired with the Royal Tree Mizuki. Fuku and Mizune are bonded together into one ship.
Spring Year 4	Upon its maiden voyage, it jumps straight to the secret lead ship of the pirate guild, the gigantic Great Daruma. The pirates are defeated single-handedly and the leader captured. The Unko was unable jump to their aid- because it was too lucky. Seina defeats Seiryo in a public duel by accidentally tearing his belt off, exposing his underwear, and humiliating him.
Summer Year 4	Seina saves Fuku from a shadow Galaxy Army group teaming with Tarant, destroying his newest Daedalus with Zinv. D, Miki, and Kirche have their AI astrals melded with cabbits. Seina graduates from the Galaxy Police Academy. Seina's wedding with Kiriko, Amane, Ryoko Balta, and Neju is interrupted when Haruken, Gyokuren, Karen, and Suiren kidnap Seina and bring him to their home territory, the Renza Federation, in order to battle their pirate problem. The brides follow after.
Winter Year 5	After being stranded on a planet full of fantasy beasts and magic, Seina starts learning how to perform magic. At some point, Seina is able to successfully wed Kiriko, Amane, Ryoko Balta, Neju, Haruken, Gyokuren, Karen, and Suiren. But before any of these marriages, it seems he also was coerced into marrying Jovia Jovis and (apparently) Airen.
Spring Year 7	Seto leads a group of women, Masaki family and close confidants, in a conversation about what to do about Kenshi, and Rea's need to send him to Geminar to stop the monstrous Gaia from destroying that world. It is decided they will train him so he'll be ready for anything, and in the meantime, will search for a way to also retrieve him. Five generations of Masaki men also gather (mostly to complain about the women), Tenchi, Nobuyuki, Katsuhito, Emperor Azusa, Kazuki Yotsuga (Azusa's father), and Seina, taking a break away from his Renza mission with Amane and Gyokuren
Fall Year 8	Seina and company returns from Renza, Jovia Jovis comes with them. The decision is made to build a house across the lake from Tenchi's house where Seina's family can call home. Making a sort of "Earth Masaki Base." Seina is immediately tasked with being caretaker of Banjo Island as it terraforms.
Year 10-11(?)	The events of Paradise War occur. Once they finish, Shou Kukumo becomes the master of a 4th Generation Royal Treeship, born from Banjo Island itself, to protect the Earth and presumably to keep the new Pirate Nation in check. Miron Pham becomes Earth's secret representative in galactic governmental affairs.
Year 15	Tenchi is given his blessing to marry Ryoko, Ayeka, Sasami, Mihoshi, Washu, Ryo-Ohki, and Noike. It is unclear if a formal wedding was held, as there would be political barriers.
Year 16-18	Tenchi and Seina start having kids within their separate families. The final stages of Kenshi's training begin.
Year 18(?)	Kenshi is sent to Geminar, the events of Tenchi Muyo! War on Geminar occur. By this time, 2 daughters have have been born to Tenchi, Ryoko being the mother of the first and Ayeka of the second. Ryo-Ohki is also said to be pregnant. Seina has his first son, born to Kiriko.
Year 19+	According to the Tenchi IF series of doujinshi, before Kenshi's likely returns from Geminar, Tenchi has fathered a litter of three cabbit daughters by Ryo-Ohki, and daughters to Mihoshi and Noike as well. Seina has also fathered sons by Amane and Ryoko Balta.
Year 68?	One of Tenchi's children, a son, goes to the moon and meets the Astral of Masaki on the remnants of her crashed ship, they fall in love. Washu creates a body for her to reinhabit

Future

Sometime in the future - Misaki goes insane after outliving everyone she loves and cares for by a large number of years. Her true powers as the "Counteractor" (The negative result of influencing the universe to create Tenchi) become evident in her rampage as she begins destroying Jurai. She pauses as she encounters Tenchi and the young female Kagato. Kami Tenchi (Tenchi's future self) appears, sends Tenchi back to his time as he seems to start to soothe and subdue Misaki.

Trivia

• The concept of the "The Great Prehistoric Civilization", a intergalactic civilization preceding the present-day intergalactic civilizations (federations, etc.), is an older concept in science fiction, most prominently used in Star Trek: The Next Generation, in The Chase, which explains why so many space-faring races are humanoid.

References

• Tenchi Muyo! FAQ site
• Tenchiverse Translation and Theory Blog