ともなると・
These forms introduce a noteworthy stage, status, scale, occasion, or undertaking and then give a consequence typically associated with reaching it. The implication is not merely “if this happens,” but “at a level like this, significant consequences naturally follow.”
A threshold with consequences
The key is the evaluative force of も. The first part should feel like a meaningful threshold: becoming a manager, reaching a certain age, entering a final round, handling a large-scale event, or attempting something demanding. The second part then describes what normally becomes true at that level.
Typical stages and consequences
Notice that each consequence is characteristic of the stage introduced before the target.
部長ともなると、部下の失敗にも責任を負わなければならない。
Once you reach the position of department manager, you have to take responsibility for your subordinates’ mistakes as well.
Analyze五十歳にもなると、健康診断の数値が以前より気になってくる。
By the time you reach fifty, the numbers from your health checkups start to concern you more than before.
Analyze海外に新しい工場を建てるともなれば、現地の法律を詳しく調べる必要がある。
If a company is going to build a new factory overseas, it will need to examine the local laws carefully.
AnalyzeChoosing among the variants
ともなると often presents the consequence as something that naturally follows when the threshold is reached. ともなれば fits especially well when considering what would follow from a major situation or undertaking. にもなると is particularly natural with ages, amounts, and named stages because it highlights reaching that point.
A situation already undergone
三度も決勝で敗れたともなると、選手たちの落胆は大きい。
After losing in the final three times, the players’ disappointment is understandably profound.
AnalyzeThe past plain form presents an accumulated experience that has reached a consequential level.
Not every consequential condition needs the target
The broader family となったら・となれば・となると can describe any consequential change of circumstances. Adding も highlights the case as a noteworthy level or status with characteristic implications. Also keep this separate from のこととなると, which means that someone reacts in a certain way when a particular subject becomes the topic; it does not describe reaching a stage.
More examples
代表チームの監督ともなると、一つ一つの決断が大きく報道される。
Once someone becomes the national team’s coach, every decision receives major media coverage.
Analyze博士課程の最終年ともなれば、研究成果を論文としてまとめる力が求められる。
By the final year of a doctoral program, students are expected to be able to organize their research findings into a dissertation.
Analyze参加者が百人規模にもなると、会場の安全管理にも専門のスタッフが必要だ。
Once the event reaches around a hundred participants, specialist staff are needed for venue safety as well.
Analyze家を一から建てるともなれば、費用だけでなく完成までの時間も考えなければならない。
If you are going to build a house from scratch, you must consider not only the cost but also how long completion will take.
Analyze全国大会の決勝ともなると、わずかな判断の遅れが勝敗を分ける。
Once it is the final of a national tournament, even a slight delay in judgment can decide the outcome.
Analyze長年一人で店を切り盛りしてきたともなると、急な問題にも落ち着いて対応できる。
After running a shop alone for many years, a person can handle sudden problems calmly.
Analyze