user18667: I'm looking for a software where I can demonstrate games in a lecture. The software shall have these features:

usable without internet connection on a Windows 10 PC
free
input and save a game as pgn easily
import pgn possible
possibility to easily draw arrows and mark squares
add variations by moving pieces
an engine with multi-pv showing at least the best four lines
bonus: engine can be chosen by me

I've tried these: Arena (no arrows), LucasChess (no variations), Scid vs PC (no arrows), Tarrasch (no arrows), Chesspad (no arrows), Lichess studies (not offline, no choosable engine), Chessity (not offline)
UPDATE: David Miedema's answer tells me that there is a comment window in Scid vs PC, that I can draw arrows and I can even mark squares with any of a lot of signs and colors. Marking squares on the main board with ScidvsPC is a bit clumsy - you have to mark them on the comment board first and then press a button to transfer to the main board.
Also, I found out that you can add marks and arrows and one engine in Chesspad.
UPDATE 2: In  between I found out that ChessX would also suit my requirements quite well. So there are ChessX, ScidVsPC, Chessbase Reader and Chesspad which would seem to be ok.
UPDATE 3: I added the two requirements: to input and save games. I took those to be a given.

user25282: Acorn Chess meets some of these requirements but not all.  Firstly it is not free but you can download a free trial and the license cost is one time only not recurring.
It is written in Java and so runs on Windows, MacOS and Linux.
It works offline - it only uses internet if you want to check for updates.  It supports board annotation with arrows and circles in tutor edition.  It has a built in engine with 6 levels.  It also supports saving games to PGN. Loading of PGN's is coming as is a position library database.
Disclaimer: I developed Acorn Chess as I couldn't find anything that met my needs.

user7147: Chessbase Reader is free, and will do all of this.  It took me forever how to figure out how to draw arrows on the board, though - it's not obvious (click-and-drag the mouse while holding down ALT, CTRL+ALT, or SHIFT+ALT to get different colored arrows).

user24024: Did you already give Scid a really good look?
Drawing Arrows
Arrows can be drawn in two ways. In the Main Board, hold Control and click on the start square and then end square. Or in the Comment Editor arrows can be drawn (and erased) by dragging between two squares.
Of course there is Chessbase in many sorts and sizes. You're probably able to find an old version for free if you search well.
Hope this brings you a bit closer.

user15511: I have asked a similar question before: Can I host lichess server to my local machine to use the study offline?
Because I was obsessed with lichess-study, I had chosen to use it offline. If you are on a Linux (or Mac) machine, I think that's the best option you have. If you are on Windows, then installing lichess on localhost is a bit tricky and also time-consuming.
In that case, I think it's better to grab a look at the software, called Lucas Chess.
It's FREE, open-source and as well as very feature-packed. There, you can choose your own engine as you like, can draw the arrow for better understanding and also can encircle squares as your requirements in the latest edition. Hope the developers will include more features in the upcoming editions of this frequently-updated project.
Here are a few screen-shots of the software:




18667: <p>I'm looking for a software where I can demonstrate games in a lecture. The software shall have these features:</p>
<ul>
<li>usable without internet connection on a Windows 10 PC</li>
<li>free</li>
<li>input and save a game as pgn easily</li>
<li>import pgn possible</li>
<li>possibility to easily draw arrows and mark squares</li>
<li>add variations by moving pieces</li>
<li>an engine with multi-pv showing at least the best four lines</li>
<li>bonus: engine can be chosen by me</li>
</ul>
<p>I've tried these: Arena (no arrows), LucasChess (no variations), Scid vs PC (no arrows), Tarrasch (no arrows), Chesspad (no arrows), Lichess studies (not offline, no choosable engine), Chessity (not offline)</p>
<p>UPDATE: David Miedema's answer tells me that there is a comment window in Scid vs PC, that I can draw arrows and I can even mark squares with any of a lot of signs and colors. Marking squares on the main board with ScidvsPC is a bit clumsy - you have to mark them on the comment board first and then press a button to transfer to the main board.
Also, I found out that you can add marks and arrows and one engine in Chesspad.</p>
<p>UPDATE 2: In  between I found out that ChessX would also suit my requirements quite well. So there are ChessX, ScidVsPC, Chessbase Reader and Chesspad which would seem to be ok.</p>
<p>UPDATE 3: I added the two requirements: to input and save games. I took those to be a given.</p>
 25282: <p><a href="https://acornchess.com" rel="nofollow noreferrer">Acorn Chess</a> meets some of these requirements but not all.  Firstly it is not free but you can download a free trial and the license cost is one time only not recurring.</p>
<p>It is written in Java and so runs on Windows, MacOS and Linux.</p>
<p>It works offline - it only uses internet if you want to check for updates.  It supports board annotation with arrows and circles in tutor edition.  It has a built in engine with 6 levels.  It also supports saving games to PGN. Loading of PGN's is coming as is a position library database.</p>
<p>Disclaimer: I developed Acorn Chess as I couldn't find anything that met my needs.</p>
 7147: <p>Chessbase Reader is free, and will do all of this.  It took me forever how to figure out how to draw arrows on the board, though - it's not obvious (click-and-drag the mouse while holding down ALT, CTRL+ALT, or SHIFT+ALT to get different colored arrows).</p>
 24024: <p>Did you already give Scid a really good look?</p>
<h3>Drawing Arrows</h3>
<p>Arrows can be drawn in two ways. In the Main Board, hold Control and click on the start square and then end square. Or in the Comment Editor arrows can be drawn (and erased) by dragging between two squares.</p>
<p>Of course there is Chessbase in many sorts and sizes. You're probably able to find an old version for free if you search well.</p>
<p>Hope this brings you a bit closer.</p>
 15511: <p>I have asked a similar question before: <a href="https://chess.stackexchange.com/questions/30391/can-i-host-lichess-server-to-my-local-machine-to-use-the-study-offline">Can I host lichess server to my local machine to use the study offline?</a></p>
<p>Because I was obsessed with lichess-study, I had chosen to use it offline. If you are on a Linux (or Mac) machine, I think that's the best option you have. If you are on Windows, then installing lichess on localhost is a bit tricky and also time-consuming.</p>
<p>In that case, I think it's better to grab a look at the software, called <a href="https://lucaschess.pythonanywhere.com/" rel="nofollow noreferrer"><strong>Lucas Chess</strong>.</a></p>
<p>It's <strong>FREE, open-source</strong> and as well as very feature-packed. There, you can choose your own engine as you like, can draw the arrow for better understanding and also can encircle squares as your requirements in the latest edition. Hope the developers will include more features in the upcoming editions of this frequently-updated project.</p>
<p>Here are a few screen-shots of the software:</p>
<p><a href="https://i.stack.imgur.com/e8emc.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/e8emc.png" alt="lucas 0" /></a></p>
<p><a href="https://i.stack.imgur.com/GdeKQ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/GdeKQ.png" alt="lucas 2" /></a></p>
<p><a href="https://i.stack.imgur.com/6Dman.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/6Dman.png" alt="enter image description here" /></a></p>
