The difference between 時　and 時は


I know that it's correct to use は after 時, and it's also correct to omit it.
For example:

> 子供の **時** 、よく海で泳ぎました。
>
> 子供の **時は** 、よく海で泳ぎました。

How does the meaning of the sentence change when the particle is used and when
it's not? This may be a slight change, but still.




> 子供の **時** 、よく海で泳ぎました。  
>  子供の **時は** 、よく海で泳ぎました。

You might say the latter to imply...

> "I used to swim in the sea in my childhood ( _but now I don't anymore_ )."

Here, the は is functioning as the contrastive particle (対比の「は」).

* * *

You might also say the latter when responding to a question...

> "What did you often do in your childhood?"  
>  -- " _In my childhood_ , I often swam in the sea."

Here, the は is functioning as the topic particle (主題の「は」).

* * *

You'd say the former to just neutrally state that you would often swim in the
sea in your childhood.




> 子供の **時** 、よく海で泳ぎました。  
>  子供の **時は** 、よく海で泳ぎました。

You might say the latter to imply...

> "I used to swim in the sea in my childhood ( _but now I don't anymore_ )."

Here, the は is functioning as the contrastive particle (対比の「は」).

* * *

You might also say the latter when responding to a question...

> "What did you often do in your childhood?"  
>  -- " _In my childhood_ , I often swam in the sea."

Here, the は is functioning as the topic particle (主題の「は」).

* * *

You'd say the former to just neutrally state that you would often swim in the
sea in your childhood.

