Understanding としてこなかった

Question

日銀は１５日、毎日実施している特定の利回りで国債を無制限に買い入れる「指し値オペ」の対象銘柄を拡大して実施した。オペの対象としてこなかった償還までの期間がやや短い国債の価格が急落し、金利が急騰したことに対応した。

https://www.jiji.com/jc/article?k=2022061500505&g=eco

I understand として as "as" and 来なかった as "didn’t come". But the combination still doesn’t make sense to me. How should I understand it?

Answer 1

The strange behavior of きた

Scenario 1

• Question: How did you come here?
• Answer: （ここまで）走ってきた = Came (here) running

I assume this is your understanding of きた - to "come" or "arrive". But the article from your example uses the word quite differently. Let's forget about going places for now, and switch our focus to the duration:

Scenario 2

• Question: What have you been doing all this year to lose weight?
• Answer: 1年間ずっと走ってきた - I kept on running this entire year

It's used to express "maintaining a state". Here are some examples:

• 今日まで頑張ってきた = Kept working hard till this day
• 今日まで頑張ってこなかった = Didn't keep working hard till this day
• 今まで面倒をみてきた = Took care all this time
• 今まで面倒をみてこなかった = Didn't take care all this time

If you can accept the concept of time as the fourth dimension, it does make sense to say "maintaining a state" is similar to "coming/arriving with the state".

• physics.stackexchange.com/questions/360621/if-i-say-time-is-the-fourth-dimension-am-i-wrong
• astronomy.stackexchange.com/questions/31777/why-is-time-considered-a-fourth-dimension

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I hope that answers the "きた" part. For further understanding, here's some tips:

してこなかった is the opposite of してきた

From my experience, it's easier to parse without negatives. So let me modify the sentence from してこなかった to してきた and explain. And because the author didn't put a comma, the sentence is a bit complicating. I'll shorten the sentence using blah:

オペの対象としてきたblah

This would mean either:

• The blah that (all this time) was subject of ops.
• The blah that (all this time) was considered/regarded/treated to be subject of ops.

Reverting back to the original sentence would result with:

オペの対象としてこなかったblah

This would mean either:

• The blah that (all this time) was not subject of ops.
• The blah that (all this time) was not considered/regarded/treated to be subject of ops.

The "subject" used here doesn't mean "subject" as in "subject/predicate"

〜とする 〜としない

To make matters further complicated, one must understand the true nuance of 〜とする and 〜としない, which are the "origin" of 〜としてきた and 〜としてこなかった. But explaining this would be too much for one answer, so I won't be going over this here. This may be expressed in Japanese as:

私は「〜とする」の説明はこの回答に含めないものとする。

Which may mean either:

• I hereby de-scope the explanation of "〜とする" for this answer.
• I consider the explanation of "〜とする" out of scope for this answer.

Conclusion

So what was "deemed out of scope of the ops" all this time? Here are three possibilities, relying on common sense only and without relying on prior knowledge of this special ops regarding bonds:

1. 償還までの期間
2. 償還までの期間がやや短い国債
3. 償還までの期間がやや短い国債の価格が急落し、金利が急騰したこと

I would say the second one, only because it makes the most sense to me:

The「償還までの期間がやや短い国債」(nat. bonds with slightly shorter redemption period) were out of scope of the 指し値オペ all this time. This resulted with the price of such bonds going downhill, causing a spike in interest. So to address this situation, on the 15th, 日銀 expanded the scope and continued the daily 指し値オペ.