I was in Shinjuku (新宿にいた）とも I went to Shinjuku (新宿に行った）とも言えると思います。
漠然と「昨日」という代わりに
yesterday morning (昨日の午前中）
yesterday afternoon (昨日の午後）
last night (昨日の夜）
などの表現を使うこともできます。
What a coincidence. I was there too.- A coincidence is a remarkable concurrence of events or circumstances without apparent causal connection. This means it wasn't planned it just happened.
For example:"It was a coincidence that she was wearing a jersey like Laura's."
What a coincidence. I was there too.
- Coincedenceは何かが偶然におこるイベントや出来事です。例えば：
（英文）"It was a coincidence that she was wearing a jersey like Laura's."
（訳）ローラと同じようなジャージーを着ていたのは偶然です。
"How was your trip to Shinjuku yesterday?"
"Great thanks! I had an incredible time. I met all my old friends and we all got very drunk!"
"Well, you'll never guess what!"
"What?"
"I was there too!"
"No!"
"Yes, my boss sent me there to help with a problem in the Shinjuku office."
"Wow, amazing that we were both there at the same time!"
（英文）
"How was your trip to Shinjuku yesterday?"
"Great thanks! I had an incredible time. I met all my old friends and we all got very drunk!"
"Well, you'll never guess what!"
"What?"
"I was there too!"
"No!"
"Yes, my boss sent me there to help with a problem in the Shinjuku office."
"Wow, amazing that we were both there at the same time!"
（訳）
「昨日新宿どうだった？」
「よかったよ！ありがとう！最高な時間を過ごせたよ。昔の友達に全員会うことができてみんな酔っ払ってた！」
「信じられないことを教えてあげよう」
「何？」
「わたしもそこにいた！」
「うそ！」
「本当。私のボスにお手伝いを頼まれて新宿のオフィスへ行っていた。」
「すごい！同じ時に同じ場所にいたなんて！」
In the first sentence, you have used the adverb 'coincidentally' from the adjective 'coincidental' which means 'happening or existing at the same time'. So you may say, 'coincidentally, I was also in Shinjuku yesterday. You may also say: It is coincidental that I was also in Shinjuku yesterday.
In the second sentence, You have used the noun 'happenstance', which means 'chance or a chance situation, especially one producing a good result'. You may also say: By a strange happenstance, we were both in Shinjuku yesterday.
最初の表現では 'coincidentally' という副詞を使っています。これは 'coincidental'という形容詞の副詞形で、偶然に又は同時に起こるという意味です。
ですので、次のように言うことが出来ます。
'coincidentally, I was also in Shinjuku yesterday'
（偶然、私も昨日新宿にいたんですよ）
また、次のようにも言うことが出来ます。
'It is coincidental that I was also in Shinjuku yesterday.'
（偶然にも私も昨日新宿にいたんですよ）
2つ目の表現では 'happenstance'と言う名詞を使っています、これは偶然の出来事というような意味で、特にいい結果などの事を言います。
次のように言うことが出来ます。
'By a strange happenstance, we were both in Shinjuku yesterday.'
(不思議な偶然の一致で、私たちどちらとも昨日新宿にいたんですよ）
What a coincidence! we were BOTH in Shinjuku yesterday...what are odds?
Coincidences can be good (or bad)...in this case no harm done;-D
Although they never actually met up!
"What a coincidence! we were BOTH in Shinjuku yesterday...what are odds?"
「coincidence」は良いことについても (悪いことにも) 使われます...この場合は、悪くないですね。
実際に会ったわけではないですが。
"What a coincidence! We were BOTH in Shinjuku yesterday...what are odds?"
(すごい偶然！昨日2人とも新宿にいたなんて...すごい確率だよね)
You can tell your friend that you were in the same place too. You can also mention why you went there. Adding the word too means in addition or as well.
I spent my day in Shinjuku yesterday too, what a twist of fate.
How interesting that you were in Shinjuku I just happened to be there myself yesterday.
Ýesterday in a moment of serendipity I also decided to travel to Shinjuku.How strange that we were both there and had no idea.
To express that you were in a place at the same time as a friend and were unaware that a friend of yours was there at the same time you may call it a twist of faith, coincidence, chance or serendipity. You may say the following;
I spent my day in Shinjuku yesterday too, what a twist of fate.
How interesting that you were in Shinjuku I just happened to be there myself yesterday.
What a coincidence that you were in Shinjuku at the same time as me.
I just happened to be there by chance my self-yesterday.
Ýesterday in a moment of serendipity I also decided to travel to Shinjuku.
友達が同じ時に同じ場所にいたことに気づかなかったことを説明する場合、偶然という意味の「twist of faith」「coincidence」「chance」や「serendipity」が使えます。
I spent my day in Shinjuku yesterday too, what a twist of fate.
（昨日私も新宿にいたよ。運命のいたずらね。）
How interesting that you were in Shinjuku I just happened to be there myself yesterday.
（あなたが新宿にいたなんてすごい。昨日私もそこにたまたまいたよ。）
What a coincidence that you were in Shinjuku at the same time as me.
（私と同じときに新宿にいたなんて、なんて偶然なの。）
I just happened to be there by chance my self-yesterday.
（私も昨日たまたまそこにいたんだ。）
Yesterday in a moment of serendipity I also decided to travel to Shinjuku.
（昨日、偶然私も新宿に行くことにしました。）
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