Questions about Japanese succession

Factual Questions
1

I have a few questions about the Japanese succession as it has been in the news as of late.

  1. I don’t understand why having the crown prince’s daughter eventually succeed if she’s his only heir would break the line. Prior to the Meiji restoration I understood that females could and did succeed and that there have been Japanese Empresses. Since this tradition of sole-male succession only goes back to 1870 (for a line that claims to go back 2,000 years) and that the practice is based on emulation of Prussia as opposed to a long-standing Japanese tradition.

If the Japanese simply don’t want a female with the crown that’s one thing, but logically speaking to say that having a female “breaks the line” makes no sense to me. I understand a lot of the political reason for opposing Aiko’s succession is the simple fact that many Japanese conservatives don’t want a female on the throne. But logically I don’t understand what I’m seeing in news reports, that there’s people saying her succession would “break the 2,000 year old line” when in fact women have been a part of that line in the past.

  1. What’s with the idea about concubines? If you’re worried about the line of succession I think going to a concubine would be a bad move. The second you start having the Crown Prince involved in extra-marital relationships, I think the chance of having a concubine who may get pregnant from someone who isn’t the prince grows in likelihood. And there’s also the fact that it’s quite possible the problem with conception is Naruhito’s in the first place, and not Masako’s. I’m guessing she is the first to be blamed because of the fact she’s the woman?
2

In response to point 1, even when there has been an empress, the following emperor has been the son of another male relative (usually a semi-distant cousin), not of the empress herself. So while women have been part of the 2,000-year line, they’ve been dead ends and placeholders rather than continuing links.

3

In this case concubine means a secondary wife, not a mistress, ergo no extra-marital relationship. Until the 20th century the Emperor had multiple wives of varying ranks. The word for empress(-consort) in Japanese, “kōgō/皇后” was the title of the emperor’s chief wife. What some conservatives are arguing for is a return to polygyny for the imperial family. In fact the Shōwa Emperor (Hirohito) was the first emperor in several centuries to be born by his father’s kōgō.

4

No meaningful information is generally known about the former and discussions about the later would make great GD material.