After maxing out all your skills in Stardew Valley, youll unlock skill mastery via the Mastery Cave in the Cindersap Forest. Youll be able to improve your skills (farming, mining, foraging, fishing, and combat) even further with upgrades and item recipes thatll help any end-game Stardew player out a ton.Below, we explain how to unlock the Stardew Valleys Mastery Cave and skill mastery, what each mastery unlocks, as well as suggestions as to which one you should pick.How to unlock skill mastery and the Mastery Cave in Stardew ValleyIn order to unlock the Mastery Cave, youll need to reach rank 10 in each skill. Once you do, youll get a message that says You sense that a new way is open in the morning, if you hit max and didnt already enter the cave.The cave is in Cindersap Forest, toward the southeast side:Once everything is maxed out, youll start to accumulate Mastery Points instead of experience points. Think of it like overcapped experience points. Each mastery point you get from doing different tasks (fishing, fighting, harvesting crops, etc.) fills up one mastery bar. When the bar is full, you can then go to the Mastery Cave to learn a skill mastery. You can see how many you have on your skill menu. Skill masteries cost more as you unlock more. Heres the number of mastery points youll need for each unlock:1st skill mastery: 10,000 Mastery Points2nd skill mastery: 15,000 Mastery Points3rd skill mastery: 20,000 Mastery Points4th skill mastery: 25,000 Mastery Points5th skill mastery: 30,000 Mastery PointsThat means youll need a whopping 100,000 Mastery Points to get all five masteries, but dont worry. Since mastery points dont correlate to a specific skill, youll amass a ton quickly just from playing the game, allowing you to master all five skills.What do masteries do in Stardew Valley?Each skill has a respective mastery and mastering the skill unlocks a recipe or two and a new passive ability:Farming MasteryYoull unlock the Iridium Scythe, a tool that allows you to harvest crops with a swing of the scythe. Say goodbye to those days of individually harvesting each crop. Youll also get the recipe for the Statue of Blessings, which gives random buffs when you interact with it every day.The passive ability allows you to find golden animal crackers, which you can give to a farm animal to permanently double the output of any farm animal, except pigs.Mining MasteryYoull get two recipes: one for the Statue of the Dwarf King and one for the heavy furnace. The statue lets you choose two buffs from a list of five, including gaining extra ore, higher chances to find things like geodes, coal, and ladders, and the ability to be immune to bomb damage. The heavy furnace smelts multiple ores into bars at once, while saving you on ore.The passive ability allows you to get doubled gems from gem-filled rocks.Foraging MasteryForaging Mastery gives you two recipes: one for the mystic tree seed and one for the treasure totem. The mystic tree seed grows into a mystic tree that produces mystic syrup (needed to make treasure totems and blue grass starters). The treasure totem puts a ring of artifact dig spots around you when used.The passive ability allows you to find golden mystery boxes, which are fundamentally the same as regular boxes, though they can have auto-petters and golden animal crackers inside.Fishing MasteryYoull get the Advanced Iridium Rod, which allows you to attach two bobbers at once. Youll also get the recipe for challenge bait, which will net you three fish if you catch it perfectly.The passive ability allows you to fish up golden fishing treasure chests, which have more items than regular treasure chests.Combat MasteryYoull get two recipes: one for the anvil and one for the anvil and one for the mini-forge. The anvil lets you reroll the stats on your trinkets in exchange for three iridium bars. The mini-forge is an at-home version of the forge from the volcano dungeon.The passive ability allows you to equip trinkets.Whats the best skill mastery in Stardew Valley?Honestly, its kind of neither here nor there because you can get all five masteries. You should prioritize the ones that would affect your gameplay the most. If youre spending a ton of time fishing, then you should grab the fishing mastery first. If you love the Skull Caverns, definitely prioritize combat and mining. If youre struggling to flesh out your museum because of missing artifacts, foraging mastery will help you out.Ultimately the choice is up to you, as none of these masteries will make or break your game. If youve gotten this far, you are probably doing pretty well in the valley. (I personally picked the farming mastery because the scythe and golden animal crackers felt really useful for what I do in Stardew Valley, but mining and fishing were close second choices for me.)