For Such a Small Program, ZX81 1K Chess Sure Packs a Lot In (opens in new tab)

<div><img width="800" height="450" src=" class="attachment-large size-large wp-post-image" alt="" style="margin: 0 auto; margin-bottom: 15px;" decoding="async" loading="lazy" srcset=" 800w, 250w, 400w" sizes="auto, (max-width: 800px) 100vw, 800px" data-attachment-id="1067304" data-permalink=" data-orig-file=" data-orig-size="800,450" data-comments-opened="1" data-image-meta="{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quo...