The Battle of Saurnesia, often abbreviated as BOS, is an alliance-focused event that pits alliances against each other. The event can involve either two or three alliances, depending on the chosen time slot. Alliances are matched against opponents with a similar league grade, ensuring a competitive balance. Your alliance's league grade is determined by its win percentage in previous BOS events. Alliances start in the Rookie league, and consistent success in BOS will elevate your alliance to higher league grades, while losses will cause it to descend. I find BOS to be one of the most engaging events in Puzzles & Conquest.

The event itself lasts for one hour. The first five minutes of the event are designated as a preparation phase, during which alliances can strategize and communicate with their opponents to decide on the terms of engagement, such as whether the battle will be between two or three alliances. During this preparation time, alliances establish "safe zones." Each alliance gets to claim three of the ten available towers and one Dragon Lair as their safe zones. This means that these towers and Dragon Lair cannot be attacked by opposing alliances, and conversely, the alliance that controls them cannot attack the safe zones of their opponents. Consequently, in a three-alliance scenario, nine out of the ten towers are designated as safe, leaving the alliances to contest the remaining tower. In a two-alliance battle, the alliances will fight for the remaining towers that are not marked as safe.

Throughout the Battle of Saurnesia, alliances can capture various objectives, including Arcane Portals, Divine Fountains, and Dragon Ruins, in addition to the towers. These objectives, like the towers, provide points for their capture and continued control. The point system works as follows: an initial burst of points is awarded upon the first occupation of an objective, and then a steady stream of points is granted for as long as the alliance maintains control of that objective. The specific point values vary depending on the type of objective.

• Dragon Lair: This is a strategically important location, the first capture of this wonder awards 6000 alliance points and 1800 personal points. Holding it grants 1200 alliance points per minute and 360 personal points per minute.
• Divine Fountain: This wonder provides a healing buff, granting allies +50% heal speed when occupied. The first capture of this wonder awards 3000 alliance points and 1500 personal points. Holding it awards 600 alliance points per minute and 300 personal points per minute.
• Dragon Ruin: This wonder provides an attack buff, granting allies +50% troop attack when occupied. The first capture of this wonder awards 3000 alliance points and 1500 personal points. Holding it awards 600 alliance points per minute and 300 personal points per minute.
• Ancient Tower: This wonder provides 1200 alliance points and 1200 personal points for the first capture. Holding it awards 240 alliance points per minute and 240 personal points per minute.
• Arcane Portal: This wonder provides 1200 alliance points and 1200 personal points for the first capture. Holding it awards 240 alliance points per minute and 240 personal points per minute.
• Saurnesia: This is the starting point for the Dragon Cub Escorts and cannot be occupied.

In addition to capturing and holding wonders, alliances can also earn points by protecting Dragon Cub Escorts. These escorts travel from Saurnesia to the Dragon Lair along a random route. When the escorts pass through a wonder that is under your alliance's control, your alliance earns points. The number of points awarded depends on the destination of the Dragon Cub Escort.

• Reach Dragon Lair: 15000 Alliance Points, 4000 Personal Points
• Reach other wonders: 9000 Alliance Points, 3000 Personal Points

Players can also earn personal points through combat. In battles at strongholds and mines, both killing and losing units contribute to your personal point total. However, in Castle battles, only losing units will increase your personal points. It's important to note that alliance points are not awarded for killing or losing units in any type of battle.

The Battle of Saurnesia event unfolds in several phases.

• Stage 1: The Ancient Tower and Arcane Portal become occupy-able.
• Stage 2: After a certain amount of time, the Divine Fountain, Dragon Ruins, and Dragon Lair become occupy-able.
• Stage 3: The Dragon Cub Escort departs from Saurnesia towards the Dragon Lair.

Having a large number of troops is crucial for success in BOS. I've observed that some strong players prioritize upgrading their castles over producing a substantial number of troops. However, relying on a small number of strong troop sets is not as effective as having a larger army composed of many troop sets. In BOS, your troops can be quickly depleted after only one or two attacks, leaving you with no forces to continue participating in the event. Players who focus solely on castle upgrades often find themselves sidelined after their strongest leader is defeated.

Another issue is the significant cost in diamonds and speedups associated with *healing* higher-tier troops after battles, particularly when focusing on rapid castle upgrades. It's not a good idea to waste these valuable resources on healing troops after BOS battles, as all troops are automatically healed once the event concludes. It's more strategic to save your healing speedups for events like Military Expedition (ME), where healing is essential and troops are not automatically recovered. For this reason, it's more strategic to focus on building a large army *before* investing heavily in castle upgrades.

Scouting enemy troops and the troops you intend to send in super rallies is also very important. As you know, Cavalry has an advantage over Infantry, Infantry has an advantage over Ranged, and Ranged has an advantage over Cavalry. (Don't even get me started on Siege units!). Super rallies occur when the rally starter spends 2000 diamonds. In this case, the rally leader's buffs apply to the troops of those joining the rally. However, this is conditional. If the rally leader is an infantry player and you send ranged troops, his buffs will not apply to your ranged troops. You must understand this troop dynamic. For example, if the enemy is primarily cavalry, and your strongest ranged player initiates a super rally, you should send ranged troops to benefit from their buffs. Sending infantry or siege units in this scenario will lead to a failed attack and increased losses due to the disadvantageous troop matchup.

In BOS, don't attack aimlessly for alliance points. Instead, pay attention to the Dragon Cub Escort's path and attack objectives just before the escort reaches them. This will secure more points for your alliance. Avoid attacking objectives that are within the opponent's safe zones, as these are unassailable. Focus your attacks on undefended towers and other wonders.

Don't send full squads to your safe towers or Dragon Lairs. Since these areas are protected, they are unlikely to be attacked. Instead, send only a single troop to occupy these safe zones, or use your farm castles for this purpose. This will free up your main forces to defend or attack other, more vulnerable objectives.

For players seeking personal points, some alliances may agree to "green attacks," which involve attacking enemy castles in the last 15 minutes of the event, or launching attacks without prior warning if you are in a non-safe zone. To avoid being targeted in these attacks, you can stay within your alliance's safe zone and send your troops to defend wonders or participate in rallies.