Frequent Yato Place Names Part 8: Oya and Koya

Representative examples of Yato place names

Well, I don't think many modern people can answer immediately if asked what a Yato is, but I think quite a few people have seen Yato place names themselves.
Shibuya is a major nationwide name, and if you live in Tokyo, you have likely heard many Yato place names such as Hibiya, Setagaya, Zoshigaya, Yotsuya, and Sendagaya.
Among those Yato place names, there are some that remain in many places.
These are place names like 'Oya' or 'Oyato'.
It is not pronounced 'Otani'. In eastern Japan, it is mainly read as 'Oya' or 'Oyato'.
There are really a lot of these.
They are evenly distributed in various places.
It can truly be said that they are suitable subjects for frequent Yato place names.
For that reason, today I would like to think a little about Oya and its antonym, Koya.

The relationship between Oya and Koya

Now, if I summarize the place names with Oya and Koya that I have visited so far, it looks something like this.

Oya: 141 locations including Oya, Oyato, Oyatsu, Bessho-Oya, Kita-Oyato, Minami-Oyato, Nishi-Oya, Mae-Oya, Ushiro-Oya, Kururi-Oya, Kami-Oya, Koito-Oya, Oyazawa, Oyachi, Oyahara, Oyata, Oyaguchi, Oyaryu, etc.
Koya: 33 locations including Koyatsu, Koya, Koyata, Koyagane, Koyano, Koyajima, Koyaryu, Koyaba, etc.

...There is a considerable difference in the numbers.
Oya is overwhelmingly more common.
The 'Kamiya, Nakaya, Shimoya' and 'Maeya, Ushiroya' that I have mentioned so far had some differences, but the numbers were roughly the same.
That is because, although there are exceptions, they were basically used as a set.
On the other hand, the difference in the number of Oya and Koya is not like that.
In fact, they are often arranged as a set of Oya and Koya, but even so, Oya exists alone overwhelmingly more often.

1. Oya and Koya: Oya is far more common, and Oya often exists alone rather than as a set.

It can be said that.

Large dissected valleys, small dissected valleys

So why is Oya more common?
If you think about it a little, you should be able to guess immediately.
I mentioned before that Yato have a chain-like nature, and since there is a limit to the population that one Yato can support, people would chain-like develop surrounding dissected valleys into Yato.

When ancient people were looking for candidates for development, I think large dissected valleys appeared that much more attractive.
The problem is that dissected valleys have boundaries and a limited number of residents who can live there, so the size would be a significant condition for development.
It would not be strange to develop such a place and name it 'Oya'.
On the other hand, what if they found a small dissected valley?
'If it's this small, should I check the next valley?'
Wouldn't that happen?
In the first place, they are looking for new development candidates because there is a limit to the population that the previous Yato can support, so you wouldn't want to go out of your way to develop a small dissected valley, would you?
'Large dissected valleys are easily developed, but small dissected valleys are unlikely to be targets for development in the first place.'
Of course, there may be times when you have no choice but to develop even if it is small due to location conditions, and that is probably why the place name Koya remains, but in any case, I think that is why the number of Koya is small.

2. Large dissected valleys are likely to be new development candidates, but small dissected valleys are unlikely to be development candidates in the first place, so the number of Koya is smaller.

It is thought that this might be the case.

The meaning of Oya and Koya

Now, what do Oya and Koya mean in the first place?
I would like to think about it while looking at individual examples.

1. Naming based on size

As an easy-to-understand example, 'Koya because it is small' and 'Oya because it is large' is one of the clear answers.

It is just as it looks.
It is a naming that is literally what it says, and I don't think there is any particular problem with this.

3. Oya and Koya are often named based on the scale of the dissected valley, with larger ones named Oya and smaller ones named Koya.

It can be said.

2. Combination with other valley place names

Please take a close look at the Oya place names I visited mentioned above.
There are place names like 'Kita-oyato, Minami-oyato, Nishi-oya, Mae-oya, Ushiro-oya, and Kami-oya'.
It seems that even if you remove the character 'O' (big) and read them as 'Kitaya, Minamiyato, Nishiya, Maeya, Ushiroya, and Kamiya', they would still make perfect sense.
These are the frequent valley place names that have appeared so far, aren't they?

As shown, there are quite a few patterns where Oya place names are 'other frequent valley place names with the character 'O' (big) added'.
In other words, it is thought that they were named like 'It's a big Kitaya, so let's call it Kita-oya' or 'It's a big Minamiyato, so let's call it Minami-oyato'.
However, this naming convention is only frequently seen in Oya among Oya and Koya, and you rarely see place names like 'Kita-koya' or 'Minami-koyato' for Koya.

4. There are many patterns where Oya becomes a valley place name like XX-oya by adding 'O' (big) to other frequent valley place names.
5. In the case of Koya, unlike Oya, place names where 'Ko' (small) is added to other frequent valley place names are almost never seen.

It can be said.

Big Koya, Small Oya

The problem starts here.
Looking at Oya and Koya in various places, I noticed that there are Oya and Koya in various regions that cannot be explained by the above theory alone.
Cases where 'it is a Koya but it is big' or 'it is an Oya but it is small' often exist.

Even so, if they existed alone, one might still be able to force an explanation.
The problem is that cases where 'Oya and Koya are a set but there is almost no difference in size' or 'Oya and Koya are a set but the Koya is actually larger' are often seen.

What on earth does this mean?

The meaning of 'O' (big) and 'Ko' (small)

In Japanese, 'O' and 'Ko' do not necessarily represent physical size.
For example, it is possible for a great person to be small in stature, and conversely, a petty villain could be a giant.
The proverb 'small matters before big matters' also expresses the importance of things using big and small, not physical size.
Japanese culture has a tendency to express important things, or things closer to the mainstream, as 'O' (big), and others as 'Ko' (small).
Please take a look at this.

It may look like Oya (Big Valley) and Koya (Small Valley) are a set, but in terms of size, Koya actually looks larger.
What is important here is this ↓

There is a 'Tani' (Valley) place name.
This is the 'Mukanyato' I mentioned previously.

・No other Yato place names are seen to the south of Mukanyato
・It is a hilly area extending left and right based on the color-coded elevation map
・It is at the southern end of a cluster of Yato place names
Considering the above and the Mukanyato rule, it is highly likely that this 'Tani' was the first Yato to be developed in this area.
If so, how did development proceed after this?

Thinking about the sequence of place names, it is thought that 'Oya' was developed after 'Tani', then 'Koya', and after that, development extended to the north.
The black line is the forest beyond the head of the valley, and since it is disconnected, it is thought that development did not initially extend in that direction.
Why is 'Oya' first? You can understand this well by looking at the aerial photograph.

It is difficult to tell because a highway runs through it, but you can see that 'Tani' and 'Oya' are connected within the same dissected valley.
On the other hand, Koya has crossed the valley wall, meaning it is in the adjacent dissected valley.
As I mentioned earlier, besides importance, 'large' and 'small' have the nuance of 'main stream' versus 'other'.
There are also phrases like 'taikyoku' (big picture) and 'shokyoku' (small picture) (though 'shokyoku' is not used much).
Applying this to Yato, perhaps the valley that extended directly from the first developed land, 'Tani', and was close to the main stream (the original Yato), was named 'Oya', and the valley next to it that was far from the main stream (the original Yato) was named 'Koya'.In short, it is not a naming convention based simply on size.

6. There are cases where 'O' (Big) is attached to places of higher importance, and 'Ko' (Small) is attached to places of lower importance.

Could we not say that?

Conclusion

I have summarized it.

1. Oya is far more common than Koya, and they often exist independently rather than as a set.
2. Large dissected valleys are easily candidates for new development, but small dissected valleys are less likely to be candidates for development in the first place, so there are fewer Koya.
3. Oya and Koya are often named based on the scale of the dissected valley, with larger ones being Oya and smaller ones being Koya.
4. There are also many patterns where 'O' is added to other frequent Yato place names to become 'XX-Oya' Yato place names.
5. In the case of Koya, unlike Oya, there are almost no place names where 'Ko' is added to other frequent Yato place names.
6. There are cases where 'O' is attached to places of higher importance, and 'Ko' is attached to places of lower importance.

There may be other reasons for the naming, but for now, this is the extent of what can be inferred.
I think it is a gain just to know that it is not just about simple size.
It might be interesting to think about 'what is it important to, that makes it Oya?' or 'what is it separated from, that makes it Koya?' for Oya and Koya in various places, even outside of this example.