Shogi opening theory

What opening theory there is in Shogi?

2

There's a lot of it, naturally. Wikipedia actually has quite good information on shogi openings and castles en.wikipedia.org/wiki/Shogi_opening and there are also a handful of books in english such as Joseki at a Glance. The most detailed and up-to-date resources are mostly only available in japanese however.

2

@Windy_Valley
First you must answer the question if you want to move the rook in the beginning or not (raging rook and static rook)
Static rook games mostly consider moving the rook pawn forward.
The there is the question of opening the bishop diagonal and when opened to trade(primitve exchange), let the trade happen or avoid the trade.
The to castles. In a big difference to chess you can have many different kind of castle mostly dependend of what opening you played. There are for example (mino, anaguma, helmet, fortress) A castle is normaly some piece stationed around the king( normally panws, silver, gold, knight)
Keep in mind that as from joseki your oponent is not dependend on your choice of openings( mostly likes systems in chess).
Eg I have one game 4th file rook vs 4th file rook

So for static rook you could look for example double wing atack,
And for raging rook we have 3rd file, 4th file and central rook.

1

We mostly focus on three things on the opening stage: 1.What to protect my king (castle), 2. Which file(s) to attack, mostly the files of your Rook and not of Opponent's Rook, 3.Which material to get (Pawn ahead of self Rook, Bishop, or even Knight and Lance of one side).
The above has mentioned a lot of Static Rook or Swinging Rook, but the core idea of that is whether I want to counter attack on the other side or not.
Some systems require unique castle that is well defended against a certain ranger but not the other, which typically relates to Bishop Exchange Opening.
In terms of pieces gotten, thanks to the Drop-in Rule, when we say "Exchange a Piece", it is not trading a piece with opponent's equal material, but moving from board to hand. Many pieces have extra high value on hand to drop, but not good at starting positions.

Not static ⚓.

. .

In my view,the first step is to move bishop's diagonal pawn, or rook's ahead pawn, or central pawn. Any of which is most likely to move, because we cannot step forward other draugtsman without moving pawns. And out of these three pawns to move at first is the expression of the will to attack. But it's only human impressions, it only looks good. Theories, strategy, tactics, there may be found in accordance with your thoutfulness, good luck.

I'm Japanese and not good at English, so I use Google Translate.
At first, the pawn in front of the rook is often moved.
After that, advance the silver general to the bishop's side.
This is called "Bogin".