Originally, there were just some cards. One day I split up the cards into a main set and two expansions. I divided the expansion cards by themes; the first expansion got one-shots, decision cards, and cards with two types, while the second expansion got cards that did something on your next turn and cards that did something when you gained them.
When I showed the game to RGG, I had five expansions. During development of the main game, I briefly tried out the expansions in 16-card versions. As part of doing this, I split up the second expansion into two expansions - one for the next turn theme, another for the right now theme. Both themes seemed good enough to support an expansion. Later, when I turned everything back into 20-card expansions (which became 25 during work on Intrigue), I kept those two themes separated. The next turn theme came out as the actual second expansion, Seaside, and now finally we have come to the when-you-gain-this expansion.
A few of these cards date back to 2006, and the original expansion with both themes. More are from when I split up the themes, then more got added to get back up to 25, and of course some cards are more recent, due to the usual process of getting rid of duds and trying new things.
For most of its life, this has been an ordinary expansion. For a while there though, I was thinking maybe it would be good to do another standalone. There are various virtures to standalones; someone else can talk them up, as I know there are other people who will argue against them. Anyway it seemed good to me. And so for a bit I focused on trying to make sure the set wasn't as complex as the couple sets before it. It gets some simplicity from the when-gain theme, although some of those cards still look complicated because they need text for both the normal and when-gain abilities. This focus helped protect a few of the simpler cards, and then late in the going Jay decided it would be a normal expansion after all. So the set is 300 cards, with no tokens or anything, and had that extra push towards simplicity, which is nice. And for those of you who were wondering, this is also why the rulebook has an unprecedented number of recommended sets of 10.
Some of you are thinking, simplicity lol. No really; whatever strategic complexity the set has, it does have some simple, easy-to-play cards; it's simpler than Prosperity but more complex than Seaside. You can sit a new player down with Nomad Camp and Crossroads and so forth and while they may not know what they're doing, they won't be confused by their cards.
The when-gain theme was always the focus of the set. A few of the cards are when-buy instead; this was necessary, as I will explain for those cards. I have a few cards that latch onto when-gain from different angles, rather than just doing something when you gain them. And then, when-gain abilities are good fits for victory cards and treasure cards, so the set got three of each. Some of the victory cards died and were replaced by other ones without when-gain abilities, but there are three, see for yourself. With three victory cards and three treasures it seemed cool to have three reactions, and towards the end I managed to squeeze in a third one.
Some of you who are word people or have internet access may note that one meaning of "hinterlands" is, the land behind the coast. So even the flavor is a complement to Seaside.
Border Village: From when Hinterlands was first its own set. Originally it cost $5. I made it better by charging more. There's a trick you can't usually do.
Cache: One of the oldest cards in the set, dating back to the 2006 version, and I never changed it.
Cartographer: This started in a later set. I moved it here because I wanted another $5 that was conceptually simple. It never changed.
Crossroads: The first version was +1 Action, +1 Card per Victory card in hand. It looked crazy but wasn't very good. Then for a long time it was, +1 Card per Victory card in hand, +1 Action per Action card in hand (you revealed a second time, so ones you drew counted). People were sad to see this go, but I could not justify having a card that meant you sometimes had no clue how many Actions you had and no way to figure it out either. Then it gave +2 Actions, but that version was too strong. Giving you +3 Actions just the first time is cute, and means you can't go too nuts without other cards helping.
Develop: A card from late in the going. I had had other Remodels not work out, and didn't think Farmland was completely filling that slot. This seemed cute and worked immediately.
Duchess: Free with any regularly priced Duchy! There was a card that gave you +1 Buy when you bought it, because, why not try that. You could buy out the pile if you lowered the cost enough. Some people thought this was hilarious but some people hated it, and it wasn't hilarious enough to justify being hated. Then I thought, well, what about a card that you can just take? "In games using this, at the start of your buy phase, you may gain a copy of this." But you don't want to have to make that decision every turn. So I went with, a card that was just free with a particular other card, one that was always out of course, and picked Duchy.
It had to be a cheap terminal action, to not get taken automatically. I had been wanting to get a friendly Spy into the set, because I wanted to add that small amount of additional interaction. So, +$2, friendly Spy. As a terminal Action costing $2, it's no hot ticket, but it's an interesting option on turn one with $2, and then when you buy a Duchy, well hey, have I got a deal for you.
Embassy: I had had "draw five discard three" in Prosperity a long time ago. It had been too strong, but it didn't seem like it needed much to make it acceptable, so a when-gain penalty was a good fit. Giving the other players a Silver doesn't matter much in the long run, but on turn one it's significant.
Farmland: Another very old card, from before I split Seaside and Hinterlands. Originally it triggered on gaining it. This can cause some confusing chaining - buy Farmland, trash a card costing $4, gain a Farmland, trash another card costing $4, gain a Farmland. I might have left it as when-gain anyway, just to have everything be when-gain (possibly also limiting what you could gain to non-Farmland), but Noble Brigand had to be when-buy, so there wasn't a sufficient benefit to having this be when-gain. So the less confusing when-buy prevailed.
Fool's Gold: The top started out as worth $1 per copy you had, on a version of Ill-Gotten Gains. It needed a tortured wording to have it be that if you played three you got $3 for each, since you play them one at a time. Bill Barksdale suggested having it be $1 and then $4, which was much simpler. It's stronger when you have just two, and weaker when you have more than three, but that all worked out. Meanwhile the bottom started on a card in a later set, and bopped around a little before ending up here. At one point the Gold didn't go on top of your deck, but it's so late, it has to go there.
Haggler: From when Hinterlands was first its own set. Originally it could gain you Victory cards. Buy Province, gain Duchy, you don't need to see that too many times. And hey you can still have that experience with Border Village as an intermediary. Also originally it triggered on gaining cards (other than via Hagglers), not just buying them. So you would sometimes get what we called "Haggler explosions." Play Haggler, buy Border Village, gain a Lab via Haggler, gain a Lab for Border Village, gain a Silver for Haggler for that. Woosh, four cards. Combined with the original Farmland, you could go further. I enjoyed Haggler explosions, but they were too confusing, and the simpler version still gives you plenty of bang.
Highway: There was a point working on the set when I wanted another $5 that you could chain. It had to be simple and compelling. Bridge and Princess are old news, but Highway plays a lot differently. All those tricks that you come up with for Bridge that you never actually pull off, you can pull off with Highway.
Ill-Gotten Gains: The very first when-gain Curser was a weird action card that gave out two Confusions (blank cards, like Curses without the -1 VP, that were in the main set originally but did not survive). It didn't work out, and I changed it to a treasure worth $1, for $3, that gave out a Curse when gained. It was like that for a while, before I became convinced that it was dominating games too much. I tried it at $4, and as a Silver for $5. That version again lasted a while, but was too good. Briefly it made $1 per copy you had in play, which I moved to Fool's Gold and fixed up. Now you get $1 or $2 out of it, depending on whether or not you want to water your deck down a little. There were two versions that gave you +$1 and had you gain a Copper to your discard pile, rather than having you gain a Copper to your hand (one failed when the Coppers ran out and one didn't). Gaining Copper to your hand ultimately seemed simpler.
Inn: Long ago, there were two similar simple cards for $4 in different sets. The first was +2 Cards, +1 Action, discard a card; the second was +2 Cards, +2 Actions, discard 2 cards. For a while they both seemed fine, but eventually I decided the first one was too strong, and it is no longer with us. The second one was Inn. It was fine, it was never changing. But one day I came up with the bottom part, and needed a card to graft it onto. Inn fit and was simple enough and there it is. I briefly tried it for $6 without the discarding.
Jack of All Trades: This started out in Cornucopia. The premise, which some of you may have been wondering about, was to make an after-the-fact Moat. Did they make you discard? Draw up to five. Are they giving you Curses? Trash one. Did they muck with the top of your deck? Let's just fix that. Are they trashing your cards? Well, here's a Silver. That's how they all fit together. The original version could trash any card, but that was too strong. Also it put your deck into your discard pile rather than letting you discard the top card; again, too strong. The order of abilities also changed.
Mandarin: The top was an obvious simple thing I just hadn't done yet. I tried several different bottoms before settling on this one. One version around for a while put a card from play on top of your deck when you gained it. That has issues that Scheme cleverly resolved but I didn't want to propagate that wordiness.
Margrave: A later set for a long time had an attack that made everyone else discard down to two, then draw a card. Mathematically it seems equivalent to Militia: you discard down to three, then you discard the worst card, which on average is average for your deck, being the middle card out of five; then you draw a card, which on average is average for your deck. That math is tricky but run through it a couple times if you have to. It's the same as Militia. Well in practice it hurts way more than Militia, like you might have thought. Militia lets you keep three cards that could be a fine hand. This only let you keep two, which is rarely enough to have a good plan, and then you draw a random card, which could work out but often does not. Anyway it was around for a long time but eventually died and everyone rejoiced. Vinay Baliga suggested flipping it - they draw one then discard down to three. Sounded good, I tried it, it worked out, there it is.
Noble Brigand: First the set had a Thief variant that gave you coins instead of the Treasures. It only gave you coins for one of the Treasures, to keep it from going nuts with multiple players. So if the best Treasure you trashed was Silver, you got +$2. Well this has wording problems. Some Treasures make variable amounts or do weird things. At the same time, it was weak. So it died.
I replaced it with a card I stole from a later set. "A later set." There are only two sets after this one, and one of them is a latecomer with its own special thing going on. When I say "a later set," I mean the 8th set, which was originally the 4th set, back before I showed Dominion to RGG, when there were only five expansions (then Hinterland and Seaside were split up, and Alchemy and Cornucopia were split up, and that accounts for seven). You might think, with all the cards I stole from "a later set," that it would be hurting for cards, but man, it is not. Anyway. I stole this from "a later set."
The premise is of course Robin Hood. Steals from the rich (those with Silver and Gold), gives to the poor (those with no Treasures at all). Ignores the middle-class (those showing Copper or special Treasures) (yes the middle class includes those with Platinum, Robin Hood does not realize how valuable Platinum is okay, he lives in a forest, they don't even have Platinum there). By not trashing Coppers, it avoids being horrible, and it can even give out Coppers, although don't expect that to be too common except you know against decks that trash their Coppers.
Noble Brigand comes right out of the gates attacking. This was a fun thing that I wanted on more attacks but it only survived here and on Ill-Gotten Gains (technically not an attack, but we all know a Witch when we see one). Maybe it's for the best that you'll never experience the joy of a when-gain discard-based attack just sitting there, promising that any hand you draw might be taken away, even if no-one has even bought the card yet.
Noble Brigand triggers on buying, not gaining. This was because you could get situations that forced you to play all further attacks in slow-mo. Jester is a good example. I play Jester, I hit your Noble Brigand, oh I want one of those. Only, everyone else has already revealed their card for Jester, no-one is wasting time. I know some of the cards Brigand will hit. Maybe normally I wouldn't take Brigand, I'd make you take another one, only, there's a Gold showing over there. Okay we have to play Jester in slow-mo this game to get rid of this situation. And well that's no fun. So, it triggers on buying.
Nomad Camp: In its earliest days the set had a Woodcutter that gave you +1 Buy when you bought it. Then it gave you +$1 and +1 Buy on the turn after you bought it, and then I just put it on your deck. Duchess is what happened from taking this the other direction.
Oasis: An old card from when Hinterlands was first its own set. Never changed. Some of them have to be simple you know.
Oracle: Originally there was a card that had you look at your top two, trash them or discard them or leave them, then draw two. It was too strong, so I axed the trashing and made it a Spy-like attack. At first that had you always pick one for them to discard, putting the other back, but I found it less oppressive when they had to leave both or discard both. I tried a few when-gain triggers on this card - there was one that trashed a card from your hand when you gained it, one that Navigator'd once, and one that Chancellor'd. The Chancellor thing was cute, but made the card too attractive just for the when-gain - meaning, people bought it for that, then happened to be attacking you. The attack was just too annoying to have people buying it when they didn't really mean it.
Scheme: An old card. The premise was always the same, but the exact mechanism has varied a little. The important thing was not to have any weirdness with one-shots or duration cards or Throne Rooms played on duration cards. That's why it only works on cards that are discarded. Sometimes Scheme could work on itself, sometimes it couldn't, depending on what phrasing seemed simpler. It ended up working on itself; you can just be planning that Scheme for a while.
Silk Road: In the early days of Hinterlands being its own set, it kind of had a Victory cards sub-theme. It had four Victory cards - they were just a cute vehicle for when-gain abilities. And it had a few things that interacted with Victory cards. So naturally it got the Victory card that counts Victory cards. It never changed.
Spice Merchant: Originally this gave +1 Action +1 Buy, choose between +2 Cards and +$2. That was too strong. Then for a while it was like it is now, and then I tried it without the +$2 +1 Buy option. There had been some worries about power level, but if it was over the top it wasn't very far over, and we were picking the Lab a lot more than the Woodcutter anyway. And remember I wanted simple cards, to make the set a standalone. Well some people were very sad to see the +$2 +1 Buy option go, and it did not appear to make the card too strong after all, so there it is.
Stables: Originally you drew the cards, then discarded a Treasure. If you had no Treasure to discard, yeeha. That version was too strong.
Trader: This is two cards welded together. The bottom part was originally its own card, in the original 4th expansion. It went through many versions that tried to be good enough. It had +2 Cards on top; it was a Treasure worth $1; it was a pure Reaction with a when-gain trigger (similar to Secret Chamber's reaction). In the end it could not carry a card by itself and so I stuck it on another card that it fit well with. That other card, the top part, I made specifically to replace Apprentice. When it turned out Alchemy would be a small set, I wanted something slam-dunk awesome for it that cost $5 and had some useful interaction with Potion, and chose Apprentice, which was in this set. Obviously Apprentice does all sorts of cool things with Hinterlands cards. So when I took it out, I wanted to replace it with something else in the Salvager family that I hadn't done yet. Gain a pile of Silvers, there you go.
Tunnel: At one point the main set had a card that had you draw a card if you discarded it. It was too wonky of an ability for the main set, and the card was bad anyway, so I cut it. When Hinterlands became its own set, I made a new card with that ability, this time a Witch variant. I ended up cutting that one because I didn't want two ways to get Curses in the set, and preferred Ill-Gotten Gains.
Late in the going, I wanted something else in the set that was exotic, and decided to try another do-something-when-discarded card. This time I had you gain Gold rather than draw cards, which slightly reduced possible confusion. It was immediately popular, but there was the question of what the top should be. It had to be simple. It couldn't be say +$2 because then this would be flat-out worse than Silver in most games that had no combo. It was +2 Cards for a bit, which seemed okay.
Then it turned out Hinterlands wouldn't be a standalone after all, which gave me space for 9 more cards. A standalone only has room for 291 kingdom cards and randomizers; a normal large set can hold 300. I was already using 290 cards. So I couldn't quite fit another kingdom card, but an existing card could turn into a victory card. And I had been wanting to have a victory-reaction in the set. So I changed Tunnel to be worth 2 VP. It seemed like that might be crazy at $3, but what, why not try it? As you can see, it worked out.