Regiment Battle

Underground Treasure Chest (地下に眠る千両箱) involves exploring the vast area beneath Osaka Castle and collecting Koban. To enter, select the event banner from the sortie page.

Event Period: 11 June 2015 (Thur) 18:00 until 7 July 2015 (Tue) 14:00 Japan Standard Time.

Related events:
 * Underground Treasure Chest 2
 * Underground Treasure Chest 3

How to Play

 * Floors 1 to 50 are made to be accessible to all players. You can collect Koban by clearing the boss node on each floor, and also by stepping on normal map nodes. The reward for clearing the 50th floor is the new sword Hakata Toushirou.
 * If you return to the citadel in the middle of a map, you will restart from the beginning of that floor.
 * Floor 51 onwards is the challenge stage. Enemies from hereon are stronger so you should attempt these floors in accordance to the level of your team.
 * Once all floors have been cleared, you will replay the 100th floor for the remainder of the event.
 * In rare instances, you can obtain Hakata Toushirou by defeating the boss on the 100th floor.
 * Players who finished all 100 floors received a special background with a banner commemorating their completion of the raid on Osaka Castle.

Tips

 * After defeating the boss on each floor, you will automatically proceed to the next floor.
 * Troop health is restored at the end of each floor, as if one had returned to the citadel at the end of a map.
 * Enemy strength and floor difficulty increase every 10 floors.
 * Swords accumulate fatigue as they progress through floors.
 * Since you cannot confirm fatigue levels during sortie, it is recommended to return to citadel at regular intervals to monitor fatigue.
 * All floors within the event are normal day maps. Oodachi and Naginata have an advantage, however putting Tantou in your team will slightly increase the chances of stepping on resource nodes.
 * Clearing specific floors will give certain rewards in addition to Koban.
 * Troops and swords will be sent to the mailbox if your inventory is full

Summary of Floors
※Note: According to this tweet, based on user-submitted reported drops of floor 100, the chances of getting Hakata Toushirou as a drop is approximately 0.44%.

Rewards
The following rewards are given for clearing each floor of the Underground Treasure Chest map.

※Note: 10,000 Koban and Gold Shieldmen are only rewarded the first time Floor 100 is cleared. Subsequent clearings reward 100 Koban alone each.