Part of the mini shogi package compiled by HGM with a guide on how to download the executable program. The following description by HGM can also be found in the mini shogi package.
Because the author of Petit Shogi is unknown, and cannot be contacted, I could not ask permission to include his engine in the mini-Shogi package. Petit Shogi is free software, however, and can be downloaded easily from the author's website. But you should do the download yourself. This page will tell you exactly how.
Petit Shogi is really a GUI (supporting USI and a number of other protocols, but alas not WinBoard protocol). The project also supplies its own (USI) engine, however, called 'ssp.exe'. GUI and engine used to come together in a single zipped archive, but recently they were split, and now are distributed separately. So what you need to download is a file 'ssp.zip'. When you Open this file on download, you will see a single file ssp.exe inside it. With 'Extract all files' you should be able to unpack this into the 'PetitShogi' sub-folder of the folder where you installed WinBoard. There it will overwrite a dummy ssp.exe, which actually is the (very small) program that was responsible for making this page popup.
To get to ssp.zip, you first have to open another page, which contains the link to it. (Sorry, direct links to the zip file did not work; I tried that.) As an advance warning: this page is in Japanese! Don't let that scare you off. You will see a table with two columns and a purple heading, and in the right pane of it there are 4 lines of Japanese text. The second line should have the word 'PetitShogi.exe' in latin letters in it, however. On the line directly below that (the third line) there will be a link in Japanese (but still recognizable as a link because it is blue and underlined), which is the link you need. (If you hover your mouse pointer over that link, your browser should tell you the corresponding URL is www.geocities.jp/shogi_depot/ssp.zip .) Click that link to start the download. The page with the purple table is here.
If you succesfully installed the ssp.exe to replace the dummy, you should never get to see this page again when you start WinBoard with Petit Shogi as engine. If not, this page will continue to appear each time you try to use Petit Shogi.
This engine does not know that repetition is a lose for the first player.
[Event "MSCA Tournament Nr 7"]
[Site "i7-2600K"]
[Date "2017.01.26"]
[Round "1"]
[White "Petit Shogi"]
[Black "Lima 3.1 64bit POPCNT"]
[Result "0-1"]
[TimeControl "900+1"]
[Variant "shogi"]
[FEN "rbsgk/4p/5/P4/KGSBR[-] w 0 1"]
[SetUp "1"]
{--------------
r b s g k
. . . . p
. . . . .
P . . . .
K G S B R
white to play
--------------}
1. Sc2 Sd4 {+1.28/25 46} 2. Gb2 {-1.15/14 35} Bc4 {+1.17/26 35} 3. Gb1
{-1.10/14 34} Bb5 {+299.99/50 11} 4. Gb2 {-1.15/14 33} Bc4 {+299.99/60} 5.
Gb1 {-1.10/14 32} Bb5 {+299.99/52 26} 6. Gb2 {-1.15/14 31} Bc4
{+299.99/60 0.1} 7. Gb1 {-1.10/14 30} Bb5 {+299.99/53 40}
{Xboard adjudication: repetition} 0-1
[Event "MSCA Tournament Nr 7"]
[Site "i7-2600K"]
[Date "2017.01.26"]
[Round "4"]
[White "Petit Shogi"]
[Black "NebiyuAlien 1.46"]
[Result "0-1"]
[TimeControl "900+1"]
[Variant "shogi"]
[FEN "rbsgk/4p/5/P4/KGSBR[-] w 0 1"]
[SetUp "1"]
{--------------
r b s g k
. . . . p
. . . . .
P . . . .
K G S B R
white to play
--------------}
1. Bc2 Bc4 2. Gb2 Gd4 3. Rd1 Rb5 4. Bb1 {-1.50/14 35} Gd5 {-0.06/21 27} 5.
Bc2 {+0.45/14 35} Gd4 {+299.98/86 22} 6. Ba4 {-1.75/14 33} Rb4
{+3.20/25 25} 7. Bc2 {+2.15/14 33} Rb5 {+299.98/84 21} 8. Ba4 {-1.75/14 32}
Rb4 {+299.98/91 18} 9. Bc2 {+2.15/14 31} Rb5 {+299.98/87 20}
{Xboard adjudication: repetition} 0-1