Usage of 〜とき: different nuances


What are the differences between these sentences? How do I properly translate
them?

  1. 日本に行くとき(に)、パスポートをとります。 
  2. 日本に行くとき(に)、パスポートをとりました。

  3. 日本に行ったとき、きょうとでさくらをみたいです。 

  4. 日本に行ったとき、きょうとでさくらをみました。

In my exercises, it just says that when the verb (in the first part of each
sentence) is in the present tense, then it means we are about to do that
action (still referring to the first part). Instead, if the verb is in the
past tense, what does it mean?

To me, they all look pretty similar, but of course there's something wrong
with my reasoning.




1.When I go to Japan, I will get my passport.

2.When I went to Japan, I got my passport.

3.When I go to Japan, I want to see sakura in Kyoto.

4.When I went to Japan, I saw sakura in Kyoto.

行く in No.2 is present tense, but the following sentence is past tense, so it
means "when I went to Japan". た in No.3 sentence is not past tense but perfect
tense, so it is used in future things.

In addition, 日本に行くとき means " You have not arrived to Japan yet", 日本に行ったとき
means "You have arrived to Japan".




1.When I go to Japan, I will get my passport.

2.When I went to Japan, I got my passport.

3.When I go to Japan, I want to see sakura in Kyoto.

4.When I went to Japan, I saw sakura in Kyoto.

行く in No.2 is present tense, but the following sentence is past tense, so it
means "when I went to Japan". た in No.3 sentence is not past tense but perfect
tense, so it is used in future things.

In addition, 日本に行くとき means " You have not arrived to Japan yet", 日本に行ったとき
means "You have arrived to Japan".

