Heavenly Stem 丁 (Ding)

The ten Heavenly Stems are the upper characters of each pillar. 丁 is the 4th stem and the yin form of Fire: focused, warm and refined; a small flame that lights a specific place and needs fuel to last. When 丁 is the stem of your day pillar it becomes your Day Master; in other positions it is read through its relation to the Day Master.

Besides appearing openly on a pillar, 丁 can be hidden inside Earthly Branches. Hidden stems are weaker than visible ones but count as roots and as Ten Gods in a detailed reading.

• 午午 Wu丁 己 · main qi
• 未未 Wei己 丁 乙 · middle qi
• 戌戌 Xu戊 辛 丁 · residual qi

The twelve growth stages describe a stem's life cycle across the branches, from Birth (长生) to Peak (帝旺) to Tomb (墓). 丁 reaches Birth in 酉 You, Peak in 巳 Si and Tomb in 丑 Chou.

• 子子 ZiExtinction (绝)
• 丑丑 ChouTomb (墓)
• 寅寅 YinDeath (死)
• 卯卯 MaoSickness (病)
• 辰辰 ChenDecline (衰)
• 巳巳 SiPeak (帝旺)
• 午午 WuComing of Age (临官)
• 未未 WeiCapping (冠带)
• 申申 ShenBathing (沐浴)
• 酉酉 YouBirth (长生)
• 戌戌 XuNurture (养)
• 亥亥 HaiConception (胎)

Yin stems here follow "yang forward, yin backward". Some schools apply the yang sequence to yin stems as well.

In the sixty-pillar (甲子) cycle, a stem only pairs with branches of the same polarity, so 丁 appears in exactly six pillars. Each has a Na Yin (纳音) sound-element name from the classical table.

When 丁 is not the Day Master, its meaning depends on who is. The same character is a companion to one Day Master and an officer or wealth star to another.

• 甲甲 Jia Yang WoodHurting Officer (伤官)
• 乙乙 Yi Yin WoodEating God (食神)
• 丙丙 Bing Yang FireRob Wealth (劫财)
• 丁丁 Ding Yin FireFriend (比肩)
• 戊戊 Wu Yang EarthDirect Resource (正印)
• 己己 Ji Yin EarthIndirect Resource (偏印)
• 庚庚 Geng Yang MetalDirect Officer (正官)
• 辛辛 Xin Yin MetalSeven Killings (七杀)
• 壬壬 Ren Yang WaterDirect Wealth (正财)
• 癸癸 Gui Yin WaterIndirect Wealth (偏财)

丁 and 壬 form one of the five stem combinations, associated with Wood. Adjacent stems combine most strongly (for example month stem next to day stem). Transformation into Wood is usually only accepted when the month branch supports Wood and nothing breaks the pair.

丁 clashes with 癸: Water and Fire are in a controlling relation with the same polarity, the harshest form of the cycle.

Through the five-element cycles, 丁 (Fire) generates 戊 Wu and 己 Ji, is generated by 甲 Jia and 乙 Yi, controls 庚 Geng and 辛 Xin and is controlled by 壬 Ren and 癸 Gui. Same-polarity pairs act more forcefully; opposite-polarity pairs are gentler and often attract.

In season in summer; in autumn and winter it depends on wood (fuel) to stay alight; strong water or wind (excess metal/water) can put it out.

• Year stem: the outer environment and early years; 丁 here colours the background of the chart.
• Month stem: closest to the season and to the Day Master; 丁 here is often the most influential visible stem.
• Day stem: 丁 is the Day Master — see the 丁 Day Master guide.
• Hour stem: later life, plans and outcomes in traditional reading; 丁 here shows how the chart "finishes".

Charts on this site use the published rule set: true solar time by default, the year changes at 立春 (Start of Spring), months change at the 12 节 solar terms and the day changes at 23:00. Example charts below are computed live by the same engine.

A practical way to study 丁 is to collect a few real charts where it appears in different positions — as Day Master, as month stem and hidden in a branch — and compare how its Ten God label changes. The BaZi calculator shows the label on every pillar, so you can check each example in seconds. Pair this page with the Fire element guide and the Ten Gods overview to see the same facts from three angles: the character, its element and its relation to the Day Master.