As you know, Honinbo Doetsu is the teacher of Honinbo Dosaku.
The teacher and the pupil played " 3-5 Four Corners Fuseki" (with Yasui Sanchi, Yasui Santetsu, Aoki Guseki and Sugimura Saburozaemon).
Two matches are here.
And the matches are awesome.
I wanna know any idea on this fuseki.

Thanks in advance!

It looks like black is using it as an alternate method to build a corner shimari, then preventing white from forming shimaris with approach moves also emphasizing the 3-5. I suspect black likes the taisha joseki.

It's important to realize that this game is from a time not long removed from the idea that white didn't absolutely have to play his first move as an approach to black's komoku. Games from that long ago can be great for learning about the middle game and endgame, but for fuseki, it is often best forgotten.

This is before the development of whole-board opening theory, so it's best not to study these games for their opening. Instead you should try to integrate the old patterns you find in these games into modern opening theory. You can study old games to find these patterns, but an often easier way is to study ancient/classic texts where they directly show many old patterns with variations.

Thank you for your kind advice.
But I'm just a novice.
So it would be great if you provided with your detail explanation.

There's absolutely nothing wrong with studying old fuseki and experimenting with them.

I open with 5-3 points quite often as black.

The truth is, especially at our level, we have the freedom to play any opening we want. When someone shows us why we lose a game because of it, then we can change it. I absolutely 100% guarantee you that you won't lose in the early opening.

I lost a game once because of move 5

Could you post that game?