Why Date Selection Matters for Bidding
Many people working in construction and procurement have a habit: before submitting a bid, they flip open the almanac to check whether the day is favorable for "business" or "signing contracts." This is not mere superstition — behind it lies a fairly complete traditional framework called date selection (Ze Ri Shu, the art of choosing auspicious dates), whose core tools are the Twelve Day Officers (Shi Er Jian Chu), auspicious and inauspicious spirits, and the generating and controlling relationships among the Five Elements (Wu Xing).
Bidding is a competitive undertaking, and it differs somewhat from ordinary "contract signing." Signing a contract is a confirmation after both parties have already reached agreement — the outcome is decided. Bidding means throwing yourself into the arena with the result still unknown. From a date-selection standpoint, bidding is therefore closer to categories like "traveling in pursuit of wealth," "seeking out influential patrons," or "engaging in competitive struggle," and the emphasis in choosing a day falls there accordingly.
The Twelve Day Officers: Which Are Suited to Competition?
The Twelve Day Officers rotate through each day of the month in sequence: Jian (Establish), Chu (Remove), Man (Full), Ping (Balance), Ding (Fix), Zhi (Hold), Po (Break), Wei (Danger), Cheng (Success), Shou (Receive), Kai (Open), Bi (Close). Each officer corresponds to different suitable activities.
Jian (Establish Day) is the day of the monthly establishment — the day matching the Earthly Branch of the current month. Tradition holds that Jian days carry vigorous Yang energy and a drive toward initiative, making them suitable for travel, seeking patrons, and competitive endeavors. In many practitioners' mnemonics, bidding falls under "striving to be first," so using a Jian day has a certain logic. That said, Jian days are also considered "too forceful," and if your own BaZi (Four Pillars of Destiny) already carries intense competitive pressure, a Jian day's reinforcement can tip into a situation where both sides lose — this needs to be assessed case by case.
Cheng (Success Day) is one of the universally recognized great auspicious days: favorable for completing endeavors, for competition, and for seeking recognition. The whole point of bidding is to "succeed," so the logic of using a Cheng day is the most direct. In folk business and competitive bidding, Cheng day is the most frequently recommended choice.
Kai (Open Day) is favorable for travel, new ventures, and meeting influential people — it carries the sense of "opening the door and laying things on the table." It is reasonable to use for submitting a bid as well, especially when participating in a project tender for the first time, since Kai day carries the symbolic meaning of breaking through and opening up new ground.
Ping (Balance Day) and Shou (Receive Day) are generally considered suitable for steady, incremental work rather than competitive actions. If no better option exists, these two days are not outright unlucky — they simply lack force.
The main days to avoid are Po (Break Day) and Bi (Close Day). Po day is self-explanatory — tradition considers it inauspicious for almost everything, and competitive matters are especially contraindicated. Bi day means closing and contracting; when submitting a bid you want doors to open, so using a Bi day runs counter to that intention.
Auspicious Stars and Inauspicious Spirits: Key Factors
Beyond the Day Officers, date selection also looks at whether the day carries enhancing or diminishing spirits.
Tian De (Heavenly Virtue) and Yue De (Monthly Virtue) are the most highly regarded auspicious stars in the tradition. Each appears only once or twice per month, and whichever day they fall on, virtually all inauspicious spirits on that day are suppressed. If a bidding date happens to carry Tian De or Yue De, other conditions can afford to be less than ideal.
Tian Yi Gui Ren (Heavenly Yi Noble Person) provides a boost for matters involving "meeting influential people and receiving assistance." In a tender opening, the evaluation committee's scoring always involves a human element; days associated with Tian Yi Gui Ren are traditionally considered helpful for gaining recognition from those in positions of authority.
Jie Sha (Calamity Sha), Zai Sha (Disaster Sha), and Sui Po (Year Breaker) are the three major inauspicious spirits most contraindicated for competitive matters. Sui Po is the day directly opposing the current year's branch — it is fixed every year, and taking important competitive action on any such day throughout the year is inadvisable. Jie Sha and Zai Sha correspond to specific Earthly Branches each month; submitting a bid on either of those days is traditionally considered likely to invite unexpected changes or interference.
Yue Po (Month Breaker) is similar to Sui Po but at the monthly level — the day six positions opposite the current month's branch. For example, in the Zi month (the eleventh lunar month), Wu day is the Month Breaker. This day should also be avoided.
The Relationship Between Bidding Time and the Hour
Many people look only at the day and not the hour. In competitive matters, however, the specific shichen (two-hour period) of submission is sometimes factored in as well.
The traditional approach is: once a favorable day is identified, select from that day's hours one that generates or harmonizes with the "Day Stem" (ri gan, the Heavenly Stem of the day) and submit within that hour. For instance, if the day's Heavenly Stem is Jia or Yi (belonging to Wood), you might choose Zi hour or Hai hour (Water generates Wood) or Wu hour (Wood generates Fire, releasing energy but indicating initiative), and avoid Shen or You hour (Metal controls Wood).
That said, I hold reservations about the operation of "precision down to the hour." Tender submissions have deadlines, and you may not have the freedom to choose which hour to hand in your documents. Forcing yourself to rush in at the last minute just to hit an "auspicious hour" carries far greater risk than any benefit from the hour's favorable quality. In practice, getting the day right is sufficient; the hour is a secondary consideration.
Common Misconceptions
Misconception 1: If the almanac says "favorable for signing contracts," it must be good for bidding. Signing a contract and submitting a bid are fundamentally different actions. Signing a contract calls for days favorable to fixing and succeeding; bidding additionally requires factors favorable to competition, travel, and seeking influential patrons. You cannot rely solely on "favorable for signing contracts."
Misconception 2: Only the day matters, not the month. The Twelve Day Officers are tied to the month. The same Cheng day, in different months, carries different Heavenly Stem and Earthly Branch combinations, which interact differently with the BaZi (Four Pillars of Destiny) of the bidding company's legal representative or project manager. When conditions allow, it is best to also examine the generating and controlling relationships between the day's stem-branch and the individual's BaZi.
Misconception 3: Date selection can compensate for a lack of competitive strength. This point deserves clarity. The traditional logic of date selection is about "borrowing favorable momentum" — acting at an energetically favorable moment, given that you already have a competitive edge. If your pricing is too high or your proposal has gaps, even the best day will do very little. There is a folk saying that captures this well: "A good destiny is not as good as good luck; good luck is not as good as good timing; good timing is not as good as being good yourself."
Misconception 4: More complex date selection methods are more accurate. Some date selection services layer in Qi Men Dun Jia and Zi Bai Fei Xing for additional analysis, building ever more complex judgments. These systems each have their own validity, but the more layers you add, the greater the likelihood of internal contradictions — and you often end up unable to find any "perfect auspicious day" at all. Traditional practitioners generally agree that the foundational framework of the Twelve Day Officers plus auspicious and inauspicious spirits is already sufficient for most everyday competitive matters, and there is no need to chase excessive precision.
Date selection for bidding is, at its core, a traditional expression of risk management thinking — choosing a starting moment that flows with the current rather than against it. When putting this into practice, eliminate Sui Po and Yue Po days, prioritize Cheng and Kai days, watch for Tian De and Yue De, and you will already be doing more than most people bother with.
Articles in this column are for cultural and educational purposes only and do not constitute life advice.