TOEI’s description is confusing

In the description for the Grendizer In the TOEI’s site:

After ten years’ travel through space he reaches the earth, and comes to know Dr. Umon, a space scientist. The prince names himself Daisuke Umon, and leads a peaceful life as a member of the Umon Family.

Duke’s wandering period, “ten years”, is a matter of debate in the forum http://gonagai.forumfree.it/?t=68800126.

I discuss the issue from the assumption that time of the Mazinger stories coincides with its of our real world. Many real historical events appear in the Mazinger’s world. For example, in 1973 there was an oil crisis that affected the whole world. In the episode No. 73 of Mazinger Z which televised on April 21, 1974, oil crisis also affected the Mazinger’s world. Boss could not buy gas for Boss-borot.

Koji maneuvered Mazinger Z at the end of the Grate Mazinger. In the episode 1 of Grendizer, Koji flied over Mt. Fuji and remembered his battle using Mazinger Z. He talked to himself “now I’m not a pilot of Mazinger Z”. So time axes for Mazinger Z, Great Mazinger and Grendizer are common.

I draw a timeline chart for Mazinger world. Dates are based on TV schedules in Japan. Click in the chart, you can see in large size.

This chart includes following items found in the primary materials(DVD video itself, screenplay and setting pictures).

1. Dr. Umon said that he met Duke Fleed about two yeard ago in episode 2 (1975-10-12).
2. Daisuke Umon is 20 years old, Koji Kabuto is 18 years old : Screenplay for episode 6 (1975-11-19)
3. Maria is 13 years old in the screenplay for episode 49. (1976-09-05)
4. Dr. Umon said “Maria is 14 years old.” in episode 50 (1976-09-12).
5. The age of Duke just before the escape from Fleed is 15 years old (episode 71, setting picture)
6. The age of Maria just before the escape from Fleed is 9 years old (setting picture)

Maria’s age in Ep. 50 is changed to 16 years old in Italian version. I discuss based on Japanese version.

From item 1, Duke arrived at earth in the fall of 1973.

Maria’s birthday is unknown. Items 3. and 4. narrow Maria’s birthday from Sept. 6 to Sept. 12. Maria could be 9 years old from 1971-09-06 to 1972-09-12.

Duke’s birthday is also unknown. Duke could be 15 years old for 365 days in the period from 1969-10-15 to 1971-10-05.(Item 2.).

At the fall of the Fleed, Duke was 15 yeas old and Maria is 9 years old. The estimated period for the fall of the Fleed is from 1971-09-06 to 1971-10-05.

From item 2, Koji was 15 years old at 1972-09-11. If Koji was 15 years old at 1972-04-01, he could enter a high school. In the world of Mazinger Z, Koji is a high school student.

In the Grendizer episode 14 (1976-01-04), Dr. Umon said that this is the first time of new year celebration for Duke. However, both on 1974-01-01 and on 1975-01-01 Duke was in Japan. I think that Duke could not celebrate new year until 1976, because he received a serious wound and was under medical treatment .

Conclusion: Duke spent about two years to reach the earth. There is no discrepancy among the age of characters.

===Additional Informations===

Age of Hikaru (Venusia) and Gorou (Mizar) are 17 and 8, respectively. Dr. Umon is 50 years old. Danbei Makiba (Rigel) is 60 years old. Banta Arano is 17 yeas old. Hikaru is a second year high-school student which corresponds to an eleventh-grade student in USA. Gorou is a three-year student. Koji is introduced as a ex-pilot of Mazinger Z. These descriptions are in the screenplay No. 6.