Among the things one learns as time passes is that everyone has to age, but not everyone has to get old. One of the best ways to stay young is to keep learning. 
 
 That’s one of the reasons I’ve spent the better part of the past two years trying my hand at developing a mobile app. To be more precise, I’ve been working with a team of developers to bring into the digital age a card game that dates back to at least the Second World War, and perhaps earlier. Starting this week, I’m pleased that it is now going to have a new life thanks to modern technology. 
 
 My involvement in this game — an incredibly devilish version of solitaire — starts with one of the greatest leaders of the 20th century at one of the most tumultuous times in world history. This is that story. 
 
 On May 10, 1940, Nazi tanks overran Belgium. Hitler’s invasion of Western Europe had a number of consequences. One was for a man named Winston Churchill to become Prime Minister the day after his predecessor, Neville Chamberlain, resigned in humiliation. Another consequence was to force into exile a young Belgian government aide named André de Staercke. As they plotted to turn back the Fascist tide, De Staercke came to know Churchill under incomprehensible stress: the Luftwaffe’s nightly bombing raids of London, an America reluctant to be dragged into another world war, and an entire world that looked to be on fire. 
 
 Winston Churchill, then in his mid-sixties, was opinionated, forceful, and determined, and ever ready with a colorful quip. Once a young photographer told him that he hoped he’d be able to shoot Churchill’s picture on the prime minister’s 100th birthday. Churchill immediately replied, “I don’t see why not, young man. You look reasonably fit and healthy.” 
 
 Churchill appreciated many things — a good book, a bottle of scotch and a cigar, games of all kinds, and perhaps above all else, a keen mind. He found that last quality in young André de Staercke, then in his late twenties, who became something of a protégé to Churchill. 
 
 André de Staercke, Joyce Rumsfeld, and me, c. 1974. 
 
 I have no doubt that Prime Minister Churchill taught André number of things — but the one thing I know about for sure Churchill taught him was how to play a uniquely challenging game of solitaire. I know this because I met André de Staercke some thirty years later in 1973, after President Richard Nixon nominated me to serve as the U.S. ambassador to the North Atlantic Treaty Organization (NATO), and de Staercke, then an esteemed senior Belgian diplomat at the NATO headquarters in Brussels, taught Churchill’s game to me. 
 
 I can remember de Staercke sitting across from me on a plane somewhere over Europe playing the curious game, dizzying columns of miniature cards arrayed on the table between us. I asked him what he was playing and he proceeded to tell me the origin of the game he called Churchill Solitaire after the man we both very much admired, and the diabolical rules that make it the hardest game of solitaire — and probably the most challenging and strategic game of logic or puzzle — I’ve ever played. 
 
 Most people have played some version of Solitaire in their lives. The Churchill version, like the man himself, is far more demanding and complex. Instead of using a single deck of 52 cards, Churchill Solitaire uses two decks. Instead of the traditional 7 rows of cards, there are 10. Instead of simply moving cards so that they fit back into single-suited piles from Ace to King, Churchill Solitaire includes an extra row of six cards — the Devil’s Six — that a player has to liberate as well. 
 
 Churchill Solitaire is not a game for everyone. It takes patience and perseverance, cunning and concentration, and strategy and sacrifice. 
 
 It’s a card game that can frustrate even the most skilled player because a single move can make or break an entire game. A number of hands are simply unwinnable. But the most steadfast players will gamely soldier on to find their way to victory. 
 
 As my friend Andre de Staercke once put it to me, “What one needs in life are the pessimism of intelligence and the optimism of will.” Play a couple hands of Churchill Solitaire, and you’ll know precisely what he meant. 
 
 Over the ensuing four decades, I played this game with two miniature decks of cards across a wide table, in much the way I envision Churchill playing it (except without the cigars and the Red Label.) On long flights across the world, or when I found a quiet moment at the end of a busy day, I would clear my mind and refocus by playing a few hands of the game. I’ve found it helps improve concentration and sharpens instincts. To succeed in Churchill Solitaire, you have to envision a variety of scenarios and think a good many moves ahead. 
 
 Up until a few years ago, there were probably a dozen or so people in the entire world who knew how to play this game. These were mostly people I taught the game to — my wife, Joyce (the second best living Churchill Solitaire player I know), our children, and some assorted colleagues and friends. That was it. Winston Churchill was gone. André de Staercke, as well. And I knew I wouldn’t be around forever. There was every chance the game Churchill so enjoyed could be lost to the ages. 
 
 Then I was approached about turning this game into an “app.” I can’t say I had much of an idea of what an app even was. I had played the regular version of solitaire on my iPad, but turning Churchill Solitaire into an app of its own wasn’t something I’d ever envisioned. It wasn’t something I was sure the Churchill family would even want us to contemplate. 
 
 In January 2014, I wrote a letter to Sir Winston Churchill’s great-grandson, Mr. Randolph Churchill. I had known Randolph’s father during my days as a diplomat. I told Randolph the background of the game, my interest in calling it “Churchill Solitaire,” and wondered if the Churchill family would have any objection. 
 
 To the contrary, the Churchill family was enthusiastic about the idea — Randolph called it “a marvelous way to bring this back to life”— and they agreed to lend their name to it as well. This is not a profit-making endeavor on either of our parts. The Churchill family’s profits from the game, like mine, will go to charity. 

 
 
 Donald Rumsfeld’s latest venture is something of a surprise. (Evan Vucci/AP) 
 
 Donald Rumsfeld has an app. No, it’s not called “Angry Kurds,” or “Find My WMD” (although wouldn’t that be something?). It is a game called “Churchill Solitaire.” It is free, and it is not easy. 
 
 “No, it’s not — it’s challenging! It’s strategic,” the former secretary of Defense said on the phone Sunday, while hustling to Union Station for a train to New York, where on Monday he hawked the app on the “Today” show and talked current events: ISIS (“It’s gonna take many, many years to deal with that problem”), if he would be okay with Donald Trump as commander-in-chief (“you bet”), and George H.W. Bush’s criticism of his “arrogant” manner (“we were never close”). 
 
 (Eddie Alvarez/The Washington Post) 
 
 Rumsfeld’s evolution from Eagle Scout to app developer took root longer ago than you’d expect, in 1973, when he was U.S. ambassador to NATO. In Brussels, Rumsfeld met fellow envoy André de Staercke, who had become friendly with Winston Churchill during World War II. The British prime minister taught the Belgian diplomat his rules of solitaire, which involved two decks of cards and a diabolical modification called “the devil’s six.” De Staercke in turn taught Rumsfeld, who has been playing this complicated version ever since. He likes it for the same reason Churchill did. 
 
 Churchill “enjoyed it as a distraction from the many weighty things he was constantly considering,” Rumsfeld said. The fact that “it’s so much more complex than any card game I know of makes it a particularly interesting diversion.” 
 
 A couple years ago Rumsfeld’s former chief of staff, Keith Urbahn, suggested that the game be loosed from officialdom and shared with the masses as a free app. Revenue from sales of the premium version would go to charities that help members and veterans of the military and their families. Rumsfeld, an avid iPad user, agreed to the project. Churchill’s estate gave its blessing. 
 
 [Rumsfeld says story mischaracterized his views on Iraq] 
 
 The game begins with video footage of Churchill in full prime minister mode during the war. Skip that, and then you’re dealt a quagmire of cards, left to struggle your way out of them in classic solitaire fashion, with a couple hitches: a point system, a ticking clock, and the aforementioned devil’s six — cards separated from the rest of deck that must be moved independently, in order, into the eight piles of aces. Even the “easy” level is challenging. 
 
 “You really have to think: ‘What is the most important card I oughta have in my mind?'” Rumsfeld said. “And it often is the top card in the devil’s six, up above, because if you don’t get those off you can’t win.” 
 
 
 
 The menu of the iPhone app Churchill Solitaire. 
 
 Rumsfeld dictated around 50 memos to help guide Urbahn and a team of developers, he said — a lot of “look at this, look at that, you fixed the last problem and now there’s a new glitch.” 
 
 A review of the Rumsfeld files finds a scattering of references to the great wartime statesman. In 1963, two months into his first term in Congress, Rumsfeld wrote that a push to award honorary U.S. citizenship to Churchill would set “a bad precedent.” On the afternoon of Sept. 10, 2001, he quoted Churchill — ominously, in retrospect: “Nothing surpasses the experience of being shot at. . . and missed.” A month after the Sept. 11 attacks, he forwarded George W. Bush some thoughts on Churchill that ended with this: “War is uncertain — a thing where surprises are routine. How wars end is usually just as surprising.” 
 
 In some ways, the wars that began under Rumsfeld’s watch have yet to reach their ends. The devil’s six remains uncleared in Iraq and Afghanistan. Once you start playing, though, it’s sometimes best to keep the game going. 
 
 “On the one hand it’s dangerous to do something: It’s risky, it’s not certain, as Churchill pointed out,” Rumsfeld says, referring to U.S. engagement — and disengagement — in regional conflicts. “But on the other hand, not doing something is equally dangerous.” 
 
 A stumped player of Churchill Solitaire can ask the app for hints, or for redos. If only both were also available in real life. 
 
 Read more: 
 
 Jon Stewart claims victory over Donald Rumsfeld 
 
 Profile: An hour with Robert Gates, a man still at war 

 I wasn't sure what I expected from Donald Rumsfeld's first iOS game — as if I expected the phrase "Donald Rumsfeld's first iOS game" to exist at all — but it wasn't Churchill Solitaire. For a man so irrecoverably linked with hawkishness, jingoism, and the push for the American military invasion of Iraq, I thought a game connected with Rumsfeld would open with explosions, bald eagles, the stars and stripes fluttering against a proud red, white, and blue background. But instead of America, Churchill Solitaire focuses on one of Britain's most notable figures — Winston Churchill — and opens with archive footage of the wartime prime minister touring bombed-out cities and visiting troops. 
 
 I expected explosions and bald eagles 
 
 In fact, there's almost nothing to tie Churchill Solitaire to the former secretary of defense at all. The game's menus are understated, decorated only with pictures of Churchill himself, scattered playing cards, and a map of the UK. Its playing surface is similarly classy, with players moving cards around on a desk of digital mahogany. Churchill Solitaire is a fairly simple tweak on the classic card game, a variant with two decks of cards instead of one that was reportedly played by the wartime prime minister when he was suffering from insomnia. Churchill taught it to André de Staercke, serving as ambassador to the Allied forces for the Belgian government while it was in exile during World War II, and de Staercke in turn taught it to Rumsfeld while the American operated as US ambassador to NATO in the early 1970s. 
 
 It's tempting to think of Rumsfeld as a new-wave indie developer, coding frantically in his bedroom, but the programming work was done by others. Rumsfeld's contributions came in the form of "snowflakes," short and sharp memos he'd provide to younger staffers on the direction of the game. "Instead of capturing history, it is getting a bit artsy," he wrote on one, The Wall Street Journal says, while another complained that his team "need to do a better job on these later versions," because "they just get new glitches." As well as hands-off designer, Rumsfeld seems to have become chief tester, spending "countless hours" on beta releases of the game and signing off on "something they call 'UX.'" 
 
 The music sounds like a Japanese RPG's battle theme 
 
 The result is the most intense game of Solitaire I've ever played. Normally a meditative exercise in time-wasting, Churchill's variation on Solitaire is already trickier than normal, and it's made even more stressful by a soundtrack that sounds like a cross between a military march and a battle theme from a Japanese RPG. Rumsfeld says the money made from the app will go to charity, but that doesn't mean Churchill Solitaire will offer you mercy. "You can make a mistake very early on that can prevent you from winning a hand that would have been winnable," Rumsfeld told the WSJ. "And that is also true in life," he added. 
 
 But unlike life, Churchill Solitaire comes with undos — a limited chance to roll back bad moves — and a hints system that will point you to any possible actions. Surely, as a staunch Republican, Rumsfeld is against such form of handouts from a higher power, but George W. Bush's old right-hand man can take solace in the fact that such advances are only open to those with the financial means to buy them — packs of 15 undos or hints cost 99 cents a pop.
– Meet Donald Rumsfeld, app developer. Yes, the 83-year-old former defense secretary is behind Churchill Solitaire, available on iPhones and iPads as of last week, the Wall Street Journal reports. Rumsfeld says that while he was US ambassador to NATO in Brussels in 1973, he learned the version of solitaire Winston Churchill played during World War II to keep on top of strategic thinking. It's a supposedly more difficult version of traditional solitaire, and Rumsfeld says it requires players "to be strategic, to look around corners, to think ahead, and to never give in." The app's website describes it as "the most diabolical version of solitaire ever devised." But Rumsfeld doesn't actually know how to code, so he issued memos called "snowflakes" to his programmers using a Dictaphone. Sample: "[W]e ought to find some way we can achieve steady improvement instead of simply making new glitches." In a post at Medium, Rumsfeld explains that he decided to develop the app because few people know the game, and he was concerned it could end up lost forever. It involves two decks of cards, a timer, and complications like a "devil's row" of six cards that must be eliminated in quite a challenging fashion, the Washington Post reports. Reviewers on the App Store seem to like it, with one saying players will "feel sucked in." But another complains that Rumsfeld's involvement "sours the app for me—I still enjoy the challenge of the game but knowing Rumsfeld will be making money from it is a negative." (The Journal reports that all of Rumsfeld's profits are going to charity.) Over at Gizmodo, Kate Knibbs declares the app "Donald Rumsfeld’s best contribution to society," and at the Verge, Rich McCormick calls it "the most intense game of solitaire I've ever played."