What does 〜o tsūjite・〜o tōshite mean and how do you use it?

「友人を通じて情報を得た」「一年を通じて温暖」 — via a medium, or across a whole span. This lesson explains the meaning, connection rules, example sentences and common mistakes.

Does this JLPT N2 grammar lesson include practice questions?

Yes. It includes JLPT-style practice questions with detailed English explanations, so you can self-study for JLPT N2 for free.

“〜o tsūjite・〜o tōshite”: Through / Throughout [JLPT N2]

Content by NTJ Kuma · Nihongo to Japan editorial team · Updated July 27, 2026

「友人を通じて情報を得た」「一年を通じて温暖」 — via a medium, or across a whole span.

「友人を通じて知り合った」 — via someone or something as a bridge, or spanning a whole period

To say “we met through a friend,” 「彼とは友人を通じて知り合った」 (I got to know him through a friend) — 「〜を通(つう)じて・〜を通(とお)して」 has two main uses: ① through ～ (via someone／something as a medium) and ② throughout ～, all across ～ (spanning a whole period or extent). The two words mean almost the same and are usually interchangeable. This guide covers both uses, the subtle gap between the two words, and the division of labor with 「によって／で」 all at once.

Core: via something as a medium, or spanning a whole period／extent

「noun ＋を通じて／を通して」 has two core uses:

① through ～, via ～ (with someone／something as a medium, means):

彼とは共通の友人を通じて知り合った (I got to know him through a mutual friend).
この経験を通して、多くのことを学んだ (through this experience, I learned a lot).

② throughout ～, all across ～ (spanning a whole period or spatial extent):

この地方は一年を通じて温暖だ (this region is warm all year round).
彼は生涯を通して、研究に打ち込んだ (throughout his life, he devoted himself to research).

Feel: the core is “via someone／something as a medium (through), or spanning a whole period／extent (throughout).” Use ① achieves something via some bridge (a friend・experience・SNS); use ② takes a time／extent noun for “from start to finish, all across” (a year・a lifetime・the whole country). It corresponds to “through ～, via ～” and “throughout ～, all ～ long, all across ～.”

Attachment & forms

Use	Form	Example
medium “through”	noun ＋を通じて／を通して	友人を通じて
extent “throughout”	time／extent noun ＋を通じて／を通して	一年を通じて

Examples in use

インターネットを通じて、世界中の人とつながれる。(Through the internet, you can connect with people worldwide.) — medium
彼女とはボランティア活動を通して知り合った。(I got to know her through volunteer work.) — medium
沖縄は一年を通じて、観光客でにぎわう。(Okinawa bustles with tourists all year round.) — extent
生涯を通して、彼は信念を曲げなかった。(Throughout his life, he never bent his convictions.) — extent
政府は報道機関を通じて、方針を発表した。(The government announced the policy through the press.) — medium

⚠️ Common mistakes to avoid

① Two uses: ‘through (medium)' and ‘throughout (extent)' — don't render every one as ‘through.' This is the easiest to misread. 「〜を通じて／を通して」 has two entirely different meanings, told apart by whether what precedes is a “medium” or a “time／extent.” Use 1: through ～ (medium, means) — precedes a person／thing, “achieve something via it as a bridge”: 友人を通じて (through a friend), 経験を通して (through experience). Use 2: throughout ～, all across ～ (extent) — precedes a time or spatial extent, “from start to finish, all across”: 一年を通じて (all year round), 全国を通して (all across the country). The commonest error is mistranslating use 2 as use 1: 「一年を通じて」 is “all year round” (warm all year), not “through a year”! Test: what precedes is “person／thing” → through (medium); what precedes is “time／extent” (a year・a lifetime・the whole country) → throughout (extent).

② Precedes a noun; for extent, what precedes is time／space. Get the attachment right — what precedes is always a noun. Note use 2 especially — it precedes a noun of “time or spatial extent”: 一年・四季・生涯・一日・全国・世界. 「一年を通じて = all year round」, 「全国を通じて = all across the country」. It doesn't take a verb. Mnemonic: noun ＋を通じて／を通して = through (person／thing) or throughout (time／extent).

③ 「を通じて」 ≒ 「を通して,」 usually interchangeable (a subtle gap). This is the lesson's biggest reassurance — they mean almost the same and are interchangeable in the vast majority of cases, and exams mostly treat them as synonyms. If pressed for a subtle tendency: 「を通じて」 leans slightly toward “result, medium, written” (achieving a result via some medium, or a whole-spanning result); 「を通して」 leans slightly toward “process, active, spanning” (personally, actively spanning the whole, through the entire process). E.g. 「一年を通じて (stressing the whole year as result／extent)」 vs 「一年を通して (stressing personally spanning that whole year),」 a very subtle difference. In practice, don't agonize — the two are nearly always interchangeable. Test: when you can't decide which, both are fine — that's precisely what makes it handy.

🔄 Compare: を通じて／を通して／によって／で

Form	Emphasis	Example
〜を通じて／を通して	through (medium) or throughout (extent)	友人を通じて
〜にわたって	(time／extent) spanning the whole, lasting	3日にわたって
〜によって	by means of／due to; the agent in a passive	努力によって
〜で	a plain means, tool (colloquial, direct)	電話で

💡 Learning tip

「〜を通じて・〜を通して」 clicks with three points: ① two uses — “through (via someone／something as a medium)” (友人を通じて) and “throughout, all across (spanning a whole period／extent)” (一年を通じて = all year round); ② precedes a noun, the extent use taking time／space (a year・a lifetime・the whole country); ③ 「を通じて」 ≒ 「を通して,」 interchangeable in the vast majority of cases (subtle gap: じて leans result／written, して leans process／active — don't agonize). The commonest slip is taking 「一年を通じて」 as “through a year” — it's “all year round.” To express “achieve something via some bridge” use the medium sense; to express “from start to finish, all across” use the extent sense (for breadth／duration you can also use 〈にわたって〉). Their interchangeability makes it one of the few N2 patterns where “either choice is fine.”

❓ Quick FAQ

Q: Is 「一年を通じて」 ‘through a year' or ‘all year round'?

It's “all year round, throughout the year,” under use 2 (extent), not “through a year.” This is the phrase learners most often misread. When 「〜を通じて／を通して」 precedes a noun of “time or spatial extent,” it means “spanning a whole period／extent, from start to finish, all across”: 一年を通じて温暖だ (warm all year round — the whole year is), 四季を通じて花が咲く (flowers bloom in all seasons — spanning the four seasons), 生涯を通じて (throughout one's life — spanning a lifetime), 全国を通じて (all across the country — spanning the whole country). Here 「を通じて」 is “spanning, covering the whole,” not “via a medium.” Use 1 “through” precedes a “person／thing (medium)”: 友人を通じて (through a friend — via a friend as a bridge), 経験を通じて (through experience). Tell them apart by the preceding word: time／extent (a year・a lifetime・the whole country) → “throughout, all across”; person／thing (a friend・experience・the net) → “through, via.” So 「一年を通じて売れる商品」 is “a product that sells all year round” (extent), and 「友人を通じて紹介された」 is “introduced through a friend” (medium). Check whether what precedes is a “time／extent” or a “medium thing,” and you'll keep them straight.

Q: 「を通じて」 and 「によって」 both express ‘through some means' — how do I tell them apart?

The difference is ‘whether it's “via something as a medium／bridge.”' 「〜を通じて／を通して」 = through ～ (via someone／something as a medium, intermediary, bridge): it stresses “achieve something by way of some intermediate medium” — that medium being like a bridge or a channel: 友人を通じて知り合う (get acquainted through a friend [that bridge]), 代理店を通じて契約する (contract through an agency [that channel]), 報道を通じて知る (learn through the press [that medium]). The focus is “there's an intermediate medium／channel.” 「〜によって」 = by some means／method／cause, or the agent in a passive: it's broader, expressing “achieve by some method” (means), “due to some cause” (cause), or the “by whom” of a passive (agent): 努力によって成功した (succeeded by effort — means／cause), 地震によって倒壊した (collapsed due to the earthquake — cause), ピカソによって描かれた (painted by Picasso — the agent of a passive). Difference: 「を通じて」 specifically means “via something as a ‘medium／bridge'” (by way of an intermediary); 「によって」 is the broader “by some means／cause／agent” (not necessarily with an ‘intermediary' sense). Test: with the sense of “by way of some intermediate medium／channel” → を通じて; a plain “by some means／due to some cause／done by someone” → によって. E.g. 「SNSを通じて拡散した (spread through SNS [medium])」 uses を通じて; 「宣伝によって認知度が上がった (recognition rose by advertising [means])」 uses によって. For a “bridge／intermediary” feel use を通じて; for a plain “by／due to” use によって.