- +2 Tolerance of the true faith
- +1 Diplomatic reputation
- +1 Yearly prestige
- −5% Technology cost
- +10% Trade efficiency
- +1% Missionary strength
- −1 National unrest
- +1 Yearly legitimacy
- +10% Cavalry combat ability
- +25% Land force limit modifier
- Main article: Sukhothai events
- Main article: Sukhothai missions
Sukhothai, like its fellow brother vassal Ligor, starts in a highly precarious position: it is the vassal of Ayutthaya, one of the strongest nations in the region, and critically, Ayutthaya starts as a tributary of Ming, the leading power of the world, who does not need even a quarter of its forces to completely wipe the Sukhothai army off the map. It is impossible to become an individual tributary of Ming while being a vassal, and as such, once the player declares their independence, they will be forced to fight the Emperor of China, a terrifying prospect in 1444.
However, all is not lost. Should Ayutthaya make the critical mistake of rivaling not just one, but both of its main regional opponents, Lan Xang and Khmer, they can both be counted on to support Sukhothai's independence. The player's opportunity to strike arises once Ming declares war on the neighboring Oirat horde to enforce tributary status upon it, as Oirat resides far away from the region Sukhothai finds itself in and Ming will always send its full army towards the Oirat horde's territories. Once the Chinese armies are far enough away, Sukhothai must strike hard and fast. As Lan Xang and Khmer both revoke their support for independence at the end of each month, they must both be brought on board at the start of the month so that there is sufficient time left to declare war on Ayutthaya and have their two rivals join the war. The goal in this initial war is just to successfully siege down enough forts to gain 23% war score, which is enough to secure independence. While Ayutthaya boasts a strong army and has the other vassal Ligor on its side, those armies alone will not be enough to overcome the forces of independence. Should Ayutthaya net itself another strong regional ally, trouble may be on the horizon, but it is still possible to successfully take them down before Ming returns to exact its judgment upon Sukhothai, as both Lan Xang and Khmer boast strong armies that can fend most enemies off at least temporarily.
While not necessary, it is recommended that the player successfully attack the Ayutthayaarmy at least once with the support of their allies, as any economic or military damage inflicted upon them will come in handy once the player has stabilized and has found themselves in a position to try and take territory from their former overlord, and it will make a solid contribution to the war score for the initial war. One opportunity to do so is while the Ayutthaya army is sieging down an allied fort, offering the player the chance to be the defender as they, together with an allied army, attempt to liberate the sieged fort. To aid in doing so, the player may set their national focus to military, as doing so allows Sukhothai to beat Ayutthaya to the military tech level 4, one of the most important tech levels in the game and one that will temporarily make the Sukhothai armies significantly stronger and more able to fight the opposing Ayutthaya army even with a numerical disadvantage. However, it is even more strongly recommended to avoid taking any territory or force any concessions out of Ayutthaya other than independence, as prolonging the war significantly increases the risk of Ming returning and joining the fight. Territorial gains will come later - gaining independence is critical at the start of the game.
Once the war is won, Sukhothaimust immediately become a tributary of Ming, as doing so will pacify them and allow Sukhothai to look around them for further expansion while they wait for the truce with Ayutthaya to be up. At this point, the hard part is over, and the game becomes a classic game of waiting and exploiting opportunities until the player is strong enough to face all comers. With Lan Xang and Khmer as allies, Sukhothai is under no immediate threat of being directly attacked by anyone, allowing the player to dictate the pace of the game and look towards its neighbors to the north-west ( Lan Na, Pegu, Taungu, Hsenwi, Ava, Mong Yang and Arakan, though the player will likely find that some have already consumed others or have been consumed themselves by the threatening Bengal) for territorial expansion.
One small tip: Ayutthaya's defeat will have irrevocably destabilized them. Once the truce is up, provided more territory has been gained along the way, the player will likely find that Ayutthaya has not recovered and may thus already be attacked again without much fear of defeat. Annexing them is a key moment in the run, as Lan Xang and Khmer will likely turn on the player following the war. A conflict with Khmer in particular is unavoidable, as they greatly desire Ayutthaya's capital province of the same name and will gladly break their alliance should the player rightly take it in their own war. Should Lan Xang do the same, Sukhothai will find themselves in a power struggle with the remaining big regional powers.
After defeating Ayutthayafor a second time, Sukhothai will become a regional power in its own right, and in time, they can easily surpass Lan Xang and Khmer and become the dominant force in the area. While working towards this objective, the player will discover that two new avenues of expansion have opened up, towards the Sunni nations of Bengal to the west and Malacca to the south. Their Islamic territories, coupled with Sukhothai's national ideas, mean that taking Religious ideas, while not mandatory, is strongly recommended, though they can be delayed for a while as Bengal, a strong nation at the start of the game, often expands towards Sukhothai's region before the player can do the opposite. This means that the territories bordering the player will often follow the player's Theravada faith, which can be annexed in one go and will not be an overly dangerous source of unrest for the nation. For further aid, Sukhothai may choose to ally a neighboring Indian power, such as Orissa, and enlist their aid when fighting Bengal.
Over to the south, while Malacca will eventually become a stumbling block on the road to expansion, they can initially be a strong ally, which may come in handy after Ayutthaya's demise once Lan Xang and Khmer no longer see Sukhothai as being worthy of an alliance due to owning territory that they themselves desire. After the two immediate threats have been dealt with and more ground has been gained at Bengal's expense, however, the player will likely no longer see Malacca as being anything but an obstacle. Eliminating them opens a path to the Malaya region, and subsequently, a new possibility for expansion: exploration ideas, through populating the uncolonized territory. Between colonization, eliminating the Malayan powers (starting with Pasai and/or Siak), solidifying their presence in the starting region through eliminating Lan Xang, Khmer and Dai Viet and pushing westward into India starting with Bengal, Sukhothai, at this point, has a tremendous number of options for expansion, and with its formidable army, its brand new navy and its prosperous lands, even Ming may start looking over its shoulder, dreading the inevitable advance of the Thai liberators...