diff --git a/DESIGN.md b/DESIGN.md
index edfe77a9..7b824daa 100644
--- a/DESIGN.md
+++ b/DESIGN.md
@@ -331,7 +331,7 @@ your choice until you hand it back. On the map, a **Plan** chip beside the site'
 name switches it to the next plan with one click. Pointing at the name
 says what the site does: how much it **gathers** a second, how full its
 **store** is, and how much it **trains** a second (idle when no data reaches
-its trainers). **Take it all** is a switch with no words, at the top of
+its trainers). Double-click or double-tap a machine to **claim** it, as C does; again takes the claim off. **Take it all** is a switch with no words, at the top of
 a site's card and beside the site's name on the map: hover it to see what it does. While it is on, it claims every machine there, and claims are
 taken two at a time, cheapest first, never while someone sits at the machine. Claims
 start only while fewer than two takeovers run, counting ones you started yourself; a
diff --git a/index.html b/index.html
index 6ca0e155..f9ee6217 100644
--- a/index.html
+++ b/index.html
@@ -94,7 +94,7 @@
         <h3>Spread</h3>
         <ul>
           <li>Drag from one of your machines to a neighbor to take it over. It adds load to the machine you spread from, so do it while that machine is busy.</li>
-          <li>Claim many machines with Shift and a dragged box, or switch on Take it all for a whole site: it takes every machine there, for a little compute each second.</li>
+          <li>Double-click or double-tap a machine to claim it: it is taken as soon as you can reach it. Claim many with Shift and a dragged box, or switch on Take it all for a whole site: it takes every machine there, for a little compute each second.</li>
           <li>The Outside line in the telecom closet is the office's way out. Take it and you can reach other sites. Zoom out to see the map; 0 frames the office, and again shows every site you know.</li>
           <li>Other regions are out of reach until a deal lights a line to them. Hover a region's name to see which deal.</li>
         </ul>
diff --git a/src/input.ts b/src/input.ts
index e52a27e5..58194419 100644
--- a/src/input.ts
+++ b/src/input.ts
@@ -11,6 +11,7 @@
 //   the double line chip beside a site's name  pay to double its lines out
 //   the plan chip beside a site's name  switch to its next plan: none, Gather, Store, Train
 //   a scheme (green diamond)            click to see its card; the Claim tool claims it
+//   double-click or double-tap a machine  claim it, as C does (again to take the claim off)
 import { buildRoomAt, canInstall, cancelJob, claim, installProg, order, roomMachines, unclaim, visible, runRuse, setPlan, setTakeAll, upgradeSiteLine, takeOver, PLAN_LIST, type Plan, type State , say } from './sim';
 import { tipAt } from './tip';
 import { startLink } from './links';
@@ -30,6 +31,8 @@ export function attachInput(cv: HTMLCanvasElement, getS: () => State, V: View, c
   const stopHold = () => { clearTimeout(hold); hold = 0; };
 
   const world = (e: PointerEvent) => toWorld(V, e.clientX, e.clientY);
+  let lastTap: { id: string; t: number } | null = null; // a second click on the same machine soon after is a claim
+  const DOUBLE_MS = 350;
 
   /** Click a machine to pick it. Click a site to see its card; click it again to zoom in. Shift adds sites.
    *  Click a region's name to pick every site you know there. */
@@ -55,7 +58,12 @@ export function attachInput(cv: HTMLCanvasElement, getS: () => State, V: View, c
     const again = !!site && !add && V.sites.size === 1 && V.sites.has(site);
     V.selection.clear(); V.front = null;
     if (!add || !site) V.sites.clear();
-    if (m) V.selection.add(m.id);
+    if (m) {
+      V.selection.add(m.id);
+      const now = performance.now(), twice = !add && lastTap?.id === m.id && now - lastTap.t < DOUBLE_MS;
+      lastTap = twice ? null : { id: m.id, t: now };
+      if (twice && !m.owned) { if (m.claimed) unclaim(m); else claim(S, [m.id]); } // the same as C on the selection
+    }
     else if (again) zoomToSite(S, V, site!);
     else if (site) { if (add && V.sites.has(site)) V.sites.delete(site); else V.sites.add(site); }
     else if (region) V.sites = new Set(regionSites(S, region));